Engine Cooling System Chevrolet Express G3500

Fastener Tightening Specifications

Fastener Tightening Specifications

Adhesives, Fluids, Lubricants, and Sealers

Adhesives, Fluids, Lubricants, and Sealers

Scheme 1

Diagnostic Code Index

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Typical Scan Tool Data

RCT Sensor

Circuit/System Description

The radiator coolant temperature (RCT) sensor is a variable resistor that measures the temperature of the radiator coolant. The ECM supplies 5 V to the RCT sensor signal circuit and supplies a ground for the low reference circuit.

Conditions for Running the DTC

1. The ignition is ON, or the engine is running.
2. The battery voltage is greater than 9 V.
3. The intake air temperature (IAT) is warmer than -30°C (-22°F) or the IAT is colder than -30°C (-22°F) and the engine run time is greater than 120 s.
4. This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTC

P00B3

The ECM detects that the RCT sensor signal is less than 0.27 V, which is warmer than 137°C (279°F) for greater than 2 s.

P00B4

The ECM detects that the RCT sensor signal is greater than 4.96 V, which is colder than-39°C (-38°F) for greater than 2 s.

Action Taken When the DTC Sets

1. DTCs P00B3 and P00B4 are Type B DTCs.
2. The cooling fans will be commanded ON.
3. The A/C compressor will be commanded OFF.

Conditions for Clearing the DTC

DTCs P00B3 and P00B4 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. If the ignition has been OFF for 8 h or greater, the IAT, the ambient air temperature, and the RCT should be within 9°C (16°F) of each other. Ignition ON, observe the scan tool IAT Sensor, Ambient Air Temperature, and the RCT sensor. Compare those sensor parameters to each other to determine if the condition is current.
2. Engine running, observe the RCT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current Ambient Air Temperature, the engine run time, and the vehicle operating conditions.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B34B Radiator Coolant Temperature Sensor.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
3. Ignition ON, verify the scan tool RCT sensor parameter is at -40°C (-40°F). If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool RCT sensor parameter is greater than 142°C (288°F). If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
5. If all circuits test normal, test or replace the B34B Radiator Coolant Temperature Sensor.

Component Testing

Static Test

Measure and record the resistance of the B34B Radiator Coolant Temperature Sensor at various ambient air temperatures, then compare those measurements to the Temperature Versus Resistance table.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
2. «Engine Coolant Temperature Sensor Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Radiator Coolant Temperature Sensor

The radiator coolant temperature (RCT) sensor is a variable resistor that measures the temperature of the radiator coolant. The ECM supplies 5 V to the RCT sensor signal circuit and supplies a ground for the low reference circuit.

The following table illustrates the difference between temperature, resistance, and voltage

1. DTCs P00B3, P00B4, P0112, P0113, P0117, P0118 or P2610 are not set.
2. The ignition has been off for greater than 8 h before vehicle is started.
3. The ignition is ON, or the engine is running.
4. The intake air temperature (IAT) is greater than -7°C (19°F).
5. The fuel level is greater than 10%.
6. The DTC runs once per ignition cycle when the above conditions are met.

This DTC sets if one of the following conditions occurs for less than 1 s

1. The ECM detects the RCT sensor and the ECT sensor are greater than a predetermined intake air temperature at engine start-up.
2. The ECM detects the RCT sensor is 20°C (68°F) warmer than the ECT sensor at engine start-up and the block heater has not been detected.
3. The ECM detects the RCT sensor is 20°C (68°F) warmer than the ECT sensor at engine start-up and the engine has been cranking for greater than 10 s without a fuel level sensor DTC.

DTC P00B6 is a Type B DTC.

DTC P00B6 is a Type B DTC.

Diagnostic Aids

1. If the vehicle has sat overnight, the RCT sensor and the ECT sensor values should display within 3°C (5°F).
2. As the thermostat opens, the RCT sensor temperature should rise steadily, then stabilize once the thermostat opens completely.
3. Test the RCT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor.
4. Inspect for the correct operation of the engine cooling system and verify the correct coolant level.
5. If the condition is intermittent, allowing the vehicle to sit for greater than 8 h with the ignition OFF, may help isolate the condition. Compare the scan tool RCT and ECT temperature sensor values at Ignition ON. The RCT sensor and the ECT sensor values should display within 3°C (5°F).

Schematic Reference

Engine Controls Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. DTC P00B3, P00B4, P0117, or P0118 should not be set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
2. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks.
3. Engine idling for 15 min with the A/C OFF. NOTE: Depending on ambient temperature, it may take up to 4 min for the temperatures to equalize.
4. Increase the engine speed to 3 000 RPM. Observe the scan tool RCT and the ECT sensor parameters. The RCT and the ECT sensor parameters should be within 20°C (68°F).
5. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

1. Ignition OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor 2.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
3. Ignition ON, verify the scan tool B34B Engine Coolant Temperature Sensor 2 parameter is -40°C (-40°F). If greater than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace K20 Engine Control Module.
4. Install a 1 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool B34B Engine Coolant Temperature Sensor 2 parameter is at 150°C (302°F). If less than specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
5. If all circuits test normal, test or replace the B34B Engine Coolant Temperature Sensor 2.

Static Test

1. Ignition OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor 2.
2. Test the B34B Engine Coolant Temperature Sensor 2 by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the table and verify that the resistance «Temperature Versus Resistance»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-specifications__temperature-versus-resistance) table and verify that the resistance is within 5% of the specification. If not within the specified range, replace the B34B Engine Coolant Temperature Sensor 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup and programming
2. «Engine Coolant Temperature Sensor Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Cooling Fan Control Circuit, and Cooling Fan Control Circuit 2 Open, Low Voltage, and High Voltage Test Status with Component OFF

Cooling Fan Control Circuit, and Cooling Fan Control Circuit 2 Open, Short Gnd, and Short Volts Test Status with Component ON

The electro-viscous (EV) cooling fan clutch system enables the engine control module (ECM) to change the speed of the pulley driven cooling fan in relation to the engine speed. Ignition voltage is supplied directly to the fan clutch solenoid valve. The ECM uses two output drivers and a parallel circuit to directly control the EV fan clutch solenoid valve. The ECM controls the solenoid valve by pulse width modulating (PWM) the parallel control circuits to ground, with a solid state device called a driver. The ECM changes the cooling fan speed by increasing or decreasing the solenoid valve ON time, known as duty cycle.

1. The ignition voltage is greater than 11 volts.
2. The engine is operating.
3. The engine speed is greater than 600 RPM.
4. DTC P0480 runs continuously when the conditions above exist for greater than 3 seconds.

The ECM detects that the commanded state of the ECM driver, and the actual state of the fan clutch solenoid control circuit do not match for greater than 1 second.

DTC P0480 is a Type B DTC.

DTC P0480 is a Type B DTC.

The scan tool Cooling Fan Control Circuit 2 Test Status parameters can used in conjunction with the Cooling Fan Control Circuit Test Status parameters to verify the integrity of the individual relay control circuits. If both the scan tool Cooling Fan Control Circuit and Cooling Fan Control Circuit 2 parameters indicate Fault in the respective Open Test Status then the condition is isolated to the portion of relay control circuit that is after the splice and common to both drivers. If Fault is indicated in only Cooling Fan Control Circuit or Cooling Fan Control Circuit 2, then the condition is isolated to the respective output driver and the portion of the circuit before the splice.

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling Fan Description and Operation (w/LGH)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Engine operating, command the cooling fan clutch ON to 80 % and then OFF to 0 % with a scan tool. Observe the scan tool Test Status parameters listed below: Cooling Fan Control Circuit Open Test Status Cooling Fan Control Circuit Low Voltage Test Status Cooling Fan Control Circuit High Voltage Test Status Cooling Fan Control Circuit 2 Open Test Status Cooling Fan Control Circuit 2 Low Voltage Test Status Cooling Fan Control Circuit 2 High Voltage Test Status The parameters should display OK or Not Run in each of the commanded states.
2. Observe the DTC information with a scan tool. Verify DTC P0480 is not set.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the fan clutch solenoid valve jumper harness connector.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal B and ground. If the test lamp does not illuminate and the fuse is good Ignition OFF, and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Remove the test lamp. Test for less than 2 ohms in the G10 Cooling Fan Motor ignition circuit, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Remove the test lamp. Test for infinite resistance between the G10 Cooling Fan Motor ignition circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance test or replace the appropriate cooling fan relay. If the test lamp illuminates
3. Test for 3-4 V between solenoid control circuit terminal A and ground. If less than 3 V Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Disconnect the K20 Engine Control Module harness connector X1. Test for less than 2 ohms in the control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms Test for infinite resistance between the control circuit and ground If less than infinite, repair the short to ground in the circuit If Infinite resistance, test or replace the K20 Engine Control Module. If greater than 4 V
4. Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
5. Disconnect the K20 Engine Control Module harness connector X1.
6. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage in the circuit. If less than 1 V, test or replace the K20 Engine Control Module. If between 3-4 V
7. Connect a 3 A fused jumper wire between the solenoid control circuit terminal A and ground. Verify the scan tool Test Status parameters listed below transition from OK to Malfunction: Cooling Fan Low Voltage Test Status Cooling Fan 2 Low Voltage Test Status If one parameter did not transition
8. Test for less than 2 ohms in the appropriate control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If both parameters transition
9. Test or replace the cooling fan clutch assembly.

EV Fan Clutch Solenoid Valve Test-Static

1. Disconnect the fan clutch jumper harness connector X142.
2. Test for 5-12 ohms between terminal B and terminal A of the jumper harness connector. If not within the specified range, replace the fan clutch assembly.
3. Measure the resistance between the terminals listed below. The DMM should display OL. B and C B and D B and E B and the fan clutch housing/ground If less than the specified range, test the circuits of the jumper harness for an open/shorted condition. If the jumper harness tests normal, replace the cooling fan clutch assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Cooling Fan Control Circuit, and Cooling Fan Control Circuit 2 Open, Low Voltage, and High Voltage Test Status with Component OFF

Cooling Fan Control Circuit, and Cooling Fan Control Circuit 2 Open, Short Gnd, and Short Volts Test Status with Component ON

The electro-viscous (EV) cooling fan clutch system enables the engine control module (ECM) to change the speed of the pulley driven cooling fan in relation to the engine speed. Ignition voltage is supplied directly to the fan clutch solenoid valve. The ECM uses two output drivers and a parallel circuit to directly control the EV fan clutch solenoid valve. The ECM controls the solenoid valve by pulse width modulating (PWM) the parallel control circuits to ground, with a solid state device called a driver. The ECM changes the cooling fan speed by increasing or decreasing the solenoid valve ON time, known as duty cycle.

1. DTC P0016, P007C, P007D, P0112, P0113, P0117, P0118, P0335, P0336, P0340, P0341, P0480, P0495, or P0526 is not set.
2. The engine is operating for greater than 10 seconds.
3. The engine speed is between 1,200-3,429 RPM.
4. The BARO is greater than 75 kPa.
5. The engine coolant temperature is warmer than 70°C (158°F).
6. The ECM commanded fan clutch solenoid duty cycle is greater than 36 percent.
7. The cooling fan input shaft speed is steady.
8. DTC P0483 runs continuously every 100 mS when the conditions above exist.

1. The difference between the desired and the actual cooling fan speeds is 500 RPM or greater.
2. The condition exists for greater than 2 minutes.

DTC P0483 is a Type B DTC.

DTC P0483 is a Type B DTC.

The scan tool Cooling Fan Control Circuit 2 Test Status parameters can used in conjunction with the Cooling Fan Control Circuit Test Status parameters to verify the integrity of the individual relay control circuits. If both the scan tool Cooling Fan Control Circuit and Cooling Fan Control Circuit 2 parameters indicate Fault in the respective Open Test Status then the condition is isolated to the portion of relay control circuit that is after the splice and common to both drivers. If Fault is indicated in only Cooling Fan Control Circuit or Cooling Fan Control Circuit 2, then the condition is isolated to the respective output driver and the portion of the circuit before the splice.

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling Fan Description and Operation (w/LGH)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, inspect the cooling fan and the drive belt for the following conditions: A loose, worn, or mis-routed drive belt Oil leaks at the cooling fan clutch A free-spinning cooling fan A seized cooling fan clutch A broken cooling fan
2. Ignition ON, observe the DTC information with a scan tool. Verify DTC P0480 or P0526 is not set. If any DTCs are set Refer to «DTC P0480»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , or «DTC P0526»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) If no DTCs are set
3. Operate the engine at 1,500 RPM while slowly commanding the cooling fan clutch from 10 % to 80 %, then return to 10 %. Observe the difference between the scan tool Fan Speed and Desired Fan Speed parameters throughout the test. The difference between the parameters should be less than 500 RPM throughout the speed transition.
4. Observe the DTC information with a scan tool. Verify DTC P0483 is not set.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the fan clutch solenoid valve jumper harness connector.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal B and ground. If the test lamp does not illuminate and the fuse is good Ignition OFF, and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Remove the test lamp. Test for less than 2 ohms in the G10 Cooling Fan Motor ignition circuit, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Remove the test lamp. Test for infinite resistance between the G10 Cooling Fan Motor ignition circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance test or replace the appropriate cooling fan relay. If the test lamp illuminates
3. Test for 3-4 V between solenoid control circuit terminal A and ground. If less than 3 V Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Disconnect the K20 Engine Control Module harness connector X1. Test for less than 2 ohms in the control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms Test for infinite resistance between the control circuit and ground If less than infinite, repair the short to ground in the circuit If Infinite resistance, test or replace the K20 Engine Control Module. If greater than 4 V
4. Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
5. Disconnect the K20 Engine Control Module harness connector X1.
6. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage in the circuit. If less than 1 V, test or replace the K20 Engine Control Module. If between 3-4 V
7. Connect a 3 A fused jumper wire between the solenoid control circuit terminal A and ground. Observe the scan tool Test Status parameters listed below: Cooling Fan Low Voltage Test Status Cooling Fan 2 Low Voltage Test Status Both parameters should transition from OK to Malfunction when the control circuit is connected to ground. If one parameter did not transition
8. Test for less than 2 ohms in the appropriate control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If both parameters transition
9. Test or replace the cooling fan clutch assembly.

EV Fan Clutch Solenoid Valve Test-Static

1. Disconnect the fan clutch jumper harness connector X142.
2. Test for 5-12 ohms between terminal B and terminal A of the jumper harness connector. If not within the specified range Test or replace the fan clutch assembly If within the specified range
3. Test for infinite resistance between the terminals listed below. B and C B and D B and E B and the fan clutch housing If less than infinite resistance Test the circuits of the jumper harness for an open/shorted condition. If infinite resistance Test or replace the cooling fan clutch assembly

EV Fan Clutch Solenoid Valve Test-Dynamic

1. Ignition OFF, disconnect the fan clutch jumper harness connector X142.
2. Connect a 10 A fused jumper wire between terminal B of jumper harness connector and B+.
3. Connect a jumper wire to terminal A of the jumper harness connector.
4. Engine operating, connect the jumper wire from terminal A to ground. The fan should get much louder to indicate the clutch is engaged.
5. Disconnect the ground from the jumper wire connected to terminal A. The fan should become quiet to indicate the clutch is disengaged. If the fan clutch doesn't engage or disengage according to the test, replace the cooling fan clutch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The electro-viscous (EV) cooling fan clutch system enables the engine control module (ECM) to change the speed of the pulley driven cooling fan in relation to the engine speed. Ignition voltage is supplied directly to the fan clutch solenoid valve. The ECM uses two output drivers and a parallel circuit to directly control the EV fan clutch solenoid valve. The ECM controls the solenoid valve by pulse width modulating (PWM) the parallel control circuits to ground, with a solid state device called a driver. The ECM changes the cooling fan speed by increasing or decreasing the solenoid valve ON time, known as duty cycle.

1. DTC P0016, P0112, P0113, P0117, P0118, P0335, P0336, P0340, P0341, P0480, P0483, P0526, P2228, or P2229 is not set.
2. The engine is operating for greater than 10 seconds.
3. The engine speed is greater than 1,071 RPM.
4. The engine OFF time after the previous ignition cycle was greater than 0 seconds.
5. The ambient air temperature (AAT) is warmer than -40°C (-40°F).
6. The BARO is greater than 55 kPa.
7. The ECM commanded fan clutch solenoid duty cycle is less than 36 percent.
8. DTC P0495 runs continuously when the conditions above exist.

1. The cooling fan speed is greater than 1,500 RPM for greater than 80 seconds. OR
2. The clutch fluid pump-out, which is the time it takes for the fan clutch to disengage completely, is greater than a range of 10 minutes at sea level to 52 minutes at elevations of 6,500 ft.

DTC P0495 is a Type B DTC.

DTC P0495 is a Type B DTC.

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling Fan Description and Operation (w/LGH)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, verify the fan clutch is not seized or binding.
2. Ignition ON, observe the DTC information with a scan tool. Verify DTC P0480, P0483, or P0526 is not set, if a DTC is set diagnose that DTC first. If DTC is set refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) If P0480, P0483, or P0526 is not set
3. Engine idling at operating temperature with all accessories turned OFF, for greater than 10 minutes.
4. Observe the scan tool DTC information. Verify DTC P0495 is not set. If P0495 is set Test or replace the Cooling Fan Clutch Assembly If P0495 is not set
5. Engine at operating temperature, Operate the engine at 1,500 RPM for 2 minutes. Observe the DTC information with a scan tool. Verify DTC P0495 is not set. If P0495 is set Test or replace the Cooling Fan Clutch Assembly If P0495 is not set
6. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) uses the cooling fan speed signal in order to determine the actual fan speed in relation to the desired fan speed, and to reduce the cooling fan noise while maintaining powertrain cooling requirements. The ECM supplies a 5-volt reference and low reference circuit to the fan speed sensor in the cooling fan clutch. The speed sensor returns a signal pulse through the signal circuit in response to the reluctor track, which is also integral to the cooling fan clutch assembly.

1. The engine is operating for greater than 10 S.
2. The engine speed is greater than 550 RPM.
3. The ECM commanded fan clutch solenoid duty cycle is greater than 45 percent.
4. DTC P0526 runs continuously when the conditions above exist for greater than 30 S.

1. The ECM detects a loss of cooling fan speed signal for greater than 300 mS.
2. The ECM detects that the cooling fan speed signal is greater or less than a predetermined threshold.
3. DTC P0526 sets if either condition exists for greater than 3 S.

DTC P0526 is a Type B DTC.

DTC P0526 is a Type B DTC.

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling Fan Description and Operation (w/LGH)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. Verify DTC P06D2 is not set.
2. Engine operating, observe the scan tool Fan Speed parameter. The parameter should display a fan speed greater than 0 RPM.
3. Observe the DTC information with a scan tool. Verify DTC P0526 is not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the fan clutch harness connector X142.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between low reference circuit terminal C and ground. If greater than 5 ohms
3. Disconnect the X1 harness connector at the K20 Engine Control Module. Test for less than 2 ohms in the circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, test or replace the K20 Engine Control Module. If less than 5 ohms
4. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal E and ground. If less than 4.8 V Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Disconnect the K20 Engine Control Module harness connector X1. Test for less than 2 ohms in the control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms Test for infinite resistance between the control circuit and ground If less than infinite, repair the short to ground in the circuit If Infinite resistance, test or replace the K20 Engine Control Module. If greater than 5.2 V
5. Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
6. Disconnect the K20 Engine Control Module harness connector X1.
7. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage in the circuit. If less than 1 V, test or replace the K20 Engine Control Module. If between 4.8-5.2 V
8. Test for 4.8-5.2 V between the signal circuit terminal D and ground. If less than 4.8 V Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Disconnect the K20 Engine Control Module harness connector X1. Test for less than 2 ohms in the control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms Test for infinite resistance between the control circuit and ground If less than infinite, repair the short to ground in the circuit If Infinite resistance, test or replace the K20 Engine Control Module. If greater than 5.2 V
9. Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
10. Disconnect the K20 Engine Control Module harness connector X1.
11. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage in the circuit. If less than 1 V, test or replace the K20 Engine Control Module. If between 4.8-5.2 V
12. Test or replace the cooling fan clutch assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) uses the engine coolant temperature (ECT) sensor to monitor the engine for an over-termperature condition. This condition occurs when the coolant temperature is above a calibrated value for a calibrated length of time. The ECM will disable half of the cylinders by turning OFF the fuel injectors. By disabling half of the cylinders, the ECM is able to reduce the temperature of the coolant.

The engine is operating.

The coolant temperature is warmer than 129°C (264°F) for greater than 10 seconds.

1. DTC P1258 is a Type A DTC.
2. The engine will operate in the Overheated Engine Protection Operating Mode.
3. The engine coolant temperature indicator lamp, if equipped, will illuminate.
4. The driver information center (DIC), if equipped, may display a message.
5. If the protection mode is active and an ECT sensor DTC sets, the protection mode will activate during the next drive cycle until the ECT sensor DTC runs and passes.

DTC P1258 is a Type A DTC.

Description and Operation

1. «Cooling System Description and Operation»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Instrument Cluster Description and Operation»(/chevrolet/express-g3500/2013-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
3. «Indicator/Warning Message Description and Operation»(/chevrolet/express-g3500/2013-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
4. «Audible Warnings Description and Operation»(/chevrolet/express-g3500/2013-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges__audible-warnings-description-and-operation)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Observe the engine coolant level. The engine coolant level should be within operating range. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Ensure that the vehicle has the correct engine coolant, with correct concentration, and is not old, contaminated or contains additives. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Inspect the cooling system for the following: Leaks Kinked or pinched hoses, especially at the radiator Loose, missing, or damaged radiator air seals or deflectors The radiator and A/C condenser for any air flow obstructions or bent fins. Refer to «Engine Overheating»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .

1. Test the thermostat for correct operation. Refer to «Thermostat Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) .
2. Test the fan clutch for proper operation. Refer to «Fan Clutch Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__fan-clutch-diagnosis) .
3. Test the engine cooling system for overheating. Refer to «Engine Overheating»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .
4. Inspect the water pump and coolant flow for correct operation. Refer to «Water Pump Replacement (V6)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Water Pump Replacement (V8)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Water Pump Replacement (LMF/LY2)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Water Pump Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Inspect the engine for worn/leaking/cracked cylinder heads and engine block. Refer to «Coolant in Combustion Chamber»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-diagnostic-information-and-procedures__coolant-in-combustion-chamber) , and «Coolant in Engine Oil»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-diagnostic-information-and-procedures__coolant-in-engine-oil) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) monitors temperature difference between the engine coolant temperature (ECT) sensor and the radiator coolant temperature (RCT) sensor during a cold start-up. The purpose of this diagnostic is to analyze the engine coolant thermostat for being stuck open.

1. DTCs P00B3, P00B4, P0101, P0102, P0103, P0112, P0113, or P0114 are not set.
2. The engine run time is between 70 s and 22 m.
3. The engine coolant temperature (ECT) sensor at start-up is between -20°C to +75°C (19 to 140°F).
4. The intake air temperature (IAT) sensor is between -7°C to +75°C (-4°F to +167°F).
5. The airflow into the engine is between 11 to 100 g/s.
6. The DTC runs once per ignition cycle when the above conditions are met.

The ECM detects the engine coolant thermostat is stuck open for 160 s.

DTC P2181 is a Type B DTC

DTC P2181 is a Type B DTC

1. Insufficient vehicle interior heating is an indication of improper thermostat operation.
2. The scan tool Desired ECT Sensor and the ECT Sensor parameters should be within 5°C (9°F) when the engine is at operating temperature.
3. A resistance condition in the ECT sensor circuits may cause this DTC. This condition results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.
4. The mechanical thermostat will open at approximately 104°C (220°F). The mechanical thermostat will cycle from approximately 104°C (220°F) to approximately 98°C (208°F).

Schematic Reference

Engine Controls Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. DTC P00B3, P00B4, P00B6, P0117, P0118, P0480, or P0481 should not be set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
2. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , and «Loss of Coolant»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
3. Increase the engine speed to 3000 RPM. Observe the scan tool ECT sensor parameter. The temperature should increase to greater than 102°C (215°F). If less than the specified value, replace the Engine Coolant Thermostat.
4. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Engine Coolant Thermostat Replacement (V6) , Engine Coolant Thermostat Replacement (Diesel)

Important Preliminary Inspections Before Starting

Before using the Symptom diagnosis, perform the following

1. Perform «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) and verify all of the following items: Ensure that the engine control module (ECM) and indicator lamp are operating correctly. Ensure that there are no diagnostic trouble codes (DTCs) that are stored. Scan tool data is within a normal operating range. Refer to «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for scan tool information.
2. Verify the customer concern.
3. Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.
4. Locate the correct symptom. Perform the tests and inspections associated with the symptom.

Review the cooling fan and cooling system operation in order to familiarize yourself with the system functions.

1. «Cooling Fan Description and Operation (w/LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Cooling System Description and Operation»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)

Visual/Physical Inspection

Several of the symptom procedures call for a careful visual and physical inspection. This can lead to correcting a condition without further tests and can save time. This inspection should include the following areas

1. Ensure that the control module grounds are clean, tight, and correctly located.
2. Inspect cooling system hoses and pipes for splits, kinks, and proper connections. Inspect thoroughly for any type of a leak or a restriction.
3. Inspect for a dirty or restricted radiator and HVAC condenser.
4. Inspect for aftermarket devices which could affect the operation of the Cooling System.
5. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
6. Inspect the surge tank reservoir for the proper coolant level.

Identifying Intermittent Conditions

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movement of a component. Refer to the following for a list to help determine an intermittent condition

1. Moisture and water intrusion in connectors, terminals, and components
2. Connector mating
3. Terminal contact
4. High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
5. Harness that is located too tight, or chaffed circuits
6. High or low ambient temperature
7. High or low engine coolant temperatures
8. High underhood temperatures
9. Heat build up in component or circuit due to circuit resistance, poor terminal contact, or high electrical load
10. High or low system voltage
11. High vehicle load conditions
12. Rough road surface
13. Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
14. Incorrect installation of non-factory, aftermarket, and after factory add on accessories

If an intermittent is determined, refer to Testing for Intermittent Conditions and Poor Connections for specific strategies in diagnosing intermittent conditions.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Engine Overheating»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating)
2. «Loss of Coolant»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant)
3. «Thermostat Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis)
4. «Coolant Heater Inoperative (w/Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Coolant Heater Inoperative (Without diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
5. «Engine Fails To Reach Normal Operating Temperature»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__engine-fails-to-reach-normal-operating)
6. «Fan Clutch Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__fan-clutch-diagnosis) , except diesel

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The low engine coolant level indicator lamp is located in, and controlled by the instrument panel cluster (IPC). The engine coolant level switch is located in the engine coolant surge tank. The switch remains closed when surrounded by coolant. When the engine coolant level switch is open for greater than 10 seconds, indicating low coolant, the IPC will turn ON the Low Coolant Indicator lamp. The lamp will also illuminate for approximately 3 seconds during the display test at the start of each ignition cycle.

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

1. Ignition OFF, verify the radiator surge tank is filled to the correct level, with engine coolant.
2. Ignition ON, command the instrument cluster indicators ON and OFF with a scan tool. The low coolant indicator lamp should turn ON and OFF as commanded.
3. Engine operating, The low coolant indicator should be OFF with the engine coolant at the correct level.

Note. Circuit/System Verification must be performed before performing the Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the B33 coolant level switch.
2. Test for less than 5 ohms between the ground circuit terminal B and ground. If greater than 5 ohms If greater than the specified range, repair the open or high resistance. If greater than the specified range, repair the ground circuit connection
3. Engine operating, connect a 3 A fused jumper wire between the signal circuit terminal A and ground. Verify the low coolant indicator turns OFF. If the indicator does not turn OFF Ignition OFF, disconnect the harness connector at the P16 IPC. Test for less than 2 ohms in the signal circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms, test or replace the P16 IPC If the indicator turns OFF
4. Test or replace the B33 coolant level switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Radiator Surge Tank Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Instrument Cluster Replacement»(/chevrolet/express-g3500/2013-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
3. «Control Module References»(/chevrolet/express-g3500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references)

Engine Overheating

Engine Overheating

Loss of Coolant

Loss of Coolant

Thermostat Diagnosis

Special Tools

J 24731 Tempil Stick

Use one of the following procedures in testing for a malfunctioning thermostat.

Thermostat Test Procedure Using Tempil Sticks

The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil like device. It has a wax material containing certain chemicals which melt at a given temperature. Temperature sticks can be used to determine a thermostat's operating range, by rubbing 87°C (188°F) and 97°C (206°F) sticks on the thermostat housing.

1. Use a tempil stick in order to find the opening and the closing temperatures of the coolant thermostat. J 24731 tempil stick - 188 tempil stick melts at 87°C (188°F). The thermostat should begin to open. J 24731 tempil stick - 206 tempil stick melts at 97°C (206°F). The thermostat should be fully open.
2. Replace the coolant thermostat if it does not operate properly between this temperature range.

Thermostat Test Procedure Using Glycol

Inspect the operation of the thermostat by hanging the thermostat on a hook in a 50/50 percent solution of DEX-COOL® and clean drinkable water.

In order to inspect if the thermostat valve is opening properly, perform the following test

1. Completely submerge the thermostat in the glycol solution. The solution should be 11°C (22°F) above the temperature indicated on the thermostat valve.
2. Thoroughly agitate the solution. Under these conditions, the thermostat valve should open.

In order to inspect if the thermostat valve is closing properly, perform the following test

1. Completely submerge the thermostat in a glycol solution. The solution should be 6°C (10°F) below the temperature indicated on the thermostat valve.
2. Thoroughly agitate the solution. Under these conditions, the thermostat valve should close completely.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The coolant heater operates using 110 V AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather. The coolant heater also helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. There is an internal thermal switch in the coolant heater cord that prevents operation above -18°C (0°F). A weather shield on the cord is provided to protect the plug when not in use.

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Note. The coolant heater cord will read Open due to an internal thermal switch if the ambient temperature is above -18°C (0°F).

1. Ignition OFF, disconnect the coolant heater cord from the E19 Coolant Heater.
2. Test for 30-40 ohms between the terminals of the E19 Coolant Heater. If not within 10-20 ohms Replace the E19 Coolant Heater. If within 10-20 ohms
3. Test for infinite resistance between each terminal of the E19 Coolant Heater and ground. If less than infinite resistance Replace the E19 Coolant Heater. If infinite resistance
4. Test or replace the coolant heater cord.

Perform the Diagnostic Repair Verification after completing the diagnostic repair.

1. «Coolant Heater Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Coolant Heater Cord Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The coolant heater operates using 110 V AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather. The coolant heater also helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. There is an internal thermal switch in the coolant heater cord that prevents operation above -18°C (0°F). A weather shield on the cord is provided to protect the plug when not in use.

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/chevrolet/express-g3500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Note. The coolant heater cord will read Open due to an internal thermal switch if the ambient temperature is above -18°C (0°F).

1. Ignition OFF, disconnect the coolant heater cord from the E19 Coolant Heater.
2. Test for 30-40 ohms between the terminals of the E19 Coolant Heater. If not within 30-40 ohms Replace the E19 Coolant Heater. If within 30-40 ohms
3. Test for infinite resistance between each terminal of the E19 Coolant Heater and ground. If less than infinite resistance Replace the E19 Coolant Heater. If infinite resistance
4. Test or replace the coolant heater cord.

Perform the Diagnostic Repair Verification after completing the diagnostic repair.

1. «Coolant Heater Replacement (V8 without 6.0L)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Coolant Heater Replacement (V6)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Coolant Heater Replacement (V8)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Coolant Heater Cord Replacement (V8)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Coolant Heater Cord Replacement (V6)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)

Engine Fails To Reach Normal Operating Temperature

Engine Fails To Reach Normal Operating Temperature

Pressure Cap Testing

Special Tools

1. J 24460-01 Cooling System Pressure Tester
2. J 42401 Radiator Cap/Surge Tank Test Adapter

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the J 24460-01 cooling system pressure tester (1) with J 42401 radiator cap/surge tank test adapter (2) in order to test the pressure cap.
4. Test the pressure cap to verify the following conditions are met: Main pressure release occurs between 2 psi below and 5 psi above the rated cap pressure. The hold pressure reads greater than 3 psi below the rated cap pressure 60 seconds after initial pressure release.
5. Replace the pressure cap if the conditions in step 4 are not met.

Cooling System Leak Testing

Special Tools

1. J 24460-01 Cooling System Pressure Tester
2. J 42401 Radiator Cap/Surge Tank Test Adapter

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__pressure-cap-testing) .
3. Wash the pressure cap mating surface with water.
4. Install the J 42401 radiator cap/surge tank test adapter to the surge tank.
5. Use the J 24460-01 cooling system pressure tester in order to apply pressure to the cooling system. Do not exceed the pressure cap rating.
6. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gauge for any pressure loss.
7. Repair any leaks as required.

Fan Clutch Diagnosis

Fan Clutch Diagnosis

Special Tools

1. J 26568 Coolant and Battery Tester
2. J 38185 Hose Clamp Pliers

Draining Procedure

1. Park the vehicle on a level surface.
2. Remove the coolant pressure cap.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
4. Place a drain pan under the lower radiator hose.
5. Using the J 38185 hose clamp pliers reposition the lower radiator hose clamp at the radiator.
6. Remove the lower radiator hose from the radiator.
7. Drain the cooling system.
8. If a complete engine block drain is required, remove the engine block drain plug.
9. Inspect the coolant.
10. Follow the appropriate procedure based on the condition of the coolant. Normal in appearance-Follow the filling procedure. Discolored-Follow the flush procedure. Refer to «Flushing»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

Filling Procedure

1. Connect the lower radiator hose.
2. Using the J 38185 hose clamp pliers position the clamp into the original position on the hose.
3. If the engine block drain plug was removed, perform the following: Apply pipe sealer to the drain plug. Install the drain plug and tighten to 22 N.m (16 lb ft).
4. Lower the vehicle.
5. Using the J 38185 hose clamp pliers , position the upper radiator hose clamp at the radiator.
6. Remove the upper radiator hose from the radiator.
7. Remove the coolant air bleed hose from the radiator.
8. Place a funnel into the upper radiator hose.
9. Slowly fill the cooling system through the upper radiator hose with a 50/50 coolant mixture until the coolant comes out the coolant air bleed hose. Refer to «Approximate Fluid Capacities»(/chevrolet/express-g3500/2013-2013/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .
10. Connect the upper radiator hose to the radiator.
11. Using the J 38185 hose clamp pliers position the radiator hose clamp into the original position on the hose.
12. Connect the coolant air bleed hose to the radiator.
13. Fill the radiator with coolant through the filler neck.
14. Install the coolant pressure cap.
15. Fill the coolant overflow bottle to the full line.
16. Start the engine.
17. Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature.
18. Allow the engine to idle for 3 minutes.
19. Shut the engine OFF.
20. Allow the engine to cool.
21. Top off the coolant as necessary.
22. Inspect the concentration of the engine coolant, using the J 26568 coolant and battery tester .
23. Rinse away any excess coolant from the engine and the engine compartment.
24. Inspect the cooling system for leaks.

J 26568 Coolant and Battery Tester

1. Follow the steps below in order to remove the surge tank fill cap: Slowly rotate the cap counterclockwise. Stop rotating and allow the hissing to stop. After all the hissing stops, continue turning counterclockwise in order to remove the cap.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
3. Place a drain pan under the lower radiator hose and/or drain cock.
4. Remove quick connect snap ring.
5. Reposition the lower radiator hose and/or drain cock from the radiator.
6. Drain the cooling system.
7. If a complete engine block drain is required, remove the left and right engine block coolant drain plugs.
8. Remove the engine block coolant heater, if equipped. Refer to «Coolant Heater Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Inspect the coolant.
10. Follow the appropriate procedure based on the condition of the coolant: Normal in appearance-Follow the filling procedure. Discolored-Follow the flush procedure. Refer to «Flushing»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

1. Install the lower radiator hose and/or drain cock to the radiator.
2. Reposition the lower radiator hose and install quick connect snap ring.
3. If the left and right engine block coolant drain plugs were removed, perform the following: Apply pipe sealer to the drain plugs. Install the drain plugs and tighten to 60 N.m (44 lb ft).
4. Install the engine block coolant heater, if equipped. Refer to «Coolant Heater Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Lower the vehicle.
6. Slowly fill the cooling system with a 50/50 coolant mixture. Refer to «Approximate Fluid Capacities»(/chevrolet/express-g3500/2013-2013/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .
7. Slowly continue filling as the level goes down.
8. Start the engine.
9. Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature. Engine should reach an operating temperature of 90°C (194°F) and the upper radiator hose should be HOT.
10. Continue to run the engine at 2,000-2,500 for 5 more minutes.
11. Slowly add more coolant to the cooling system.
12. Allow the engine to idle for 5 minutes.
13. Slowly add more coolant to the cooling system.
14. Repeat steps 10 and 11.
15. Install radiator cap.
16. Shut the engine OFF.
17. Allow the engine to cool.
18. Top off the coolant as necessary.
19. Inspect the concentration of the engine coolant using the J 26568 coolant and battery tester.
20. Rinse away any excess coolant from the engine and the engine compartment.

Cooling System Draining and Filling (Vac N Fill)

Special Tools

1. GE-47716 Vac-N-Fill Coolant Refill Tool
2. J 26568 Coolant and Battery Tester
3. J 42401 Radiator Cap and Surge Tank Test Adapter

1. Park the vehicle on a level surface.
2. Remove the coolant pressure cap.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
4. Place a drain pan under the drain cock.
5. Open the radiator drain cock.
6. Drain the cooling system.
7. If a complete engine block drain is required, remove the engine block drain plug.
8. Inspect the coolant.
9. Follow the appropriate procedure based on the condition of the coolant. Normal in appearance-Follow the filling procedure. Discolored-Follow the flush procedure. Refer to «Flushing»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

Vac-N-Fill Procedure

Note. To prevent boiling of the coolant/water mixture in the vehicles cooling system, do not apply vacuum to a cooling system above 49°C (120°F). The tool will not operate properly when the coolant is boiling.

1. Install the J 42401 radiator cap and surge tank test adapter.
2. Attach the Van-N-Fill cap to the vehicles coolant fill port.
3. Attach the vacuum gauge assembly to the Vac-N-Fill cap.
4. Attach the fill hose to the barb fitting on the vacuum gauge assembly. Ensure that the valve is closed.
5. Pour the coolant mixture into the graduated reservoir.
6. Place the fill hose in the graduated reservoir.
7. Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.
8. Attach the venture assembly to the vacuum tank.
9. Attach a shop air hose to the venture assembly. Ensure the valve on the venture assembly is closed.
10. Attach the vacuum hose to the vacuum gauge assembly and the vacuum tank.
11. Clamp off the overflow hose.
12. Open the valve on the venture assembly. The vacuum gauge will begin to rise and a hissing noise will be present.
13. Continue to draw vacuum until the needle stops rising. This should be 610-660 mm Hg (24-26 in Hg). Cooling hoses may start to collapse. This is normal due to vacuum draw.
14. To aid in the fill process, position the graduated reservoir above the coolant fill port.
15. Slowly open the valve on the vacuum gauge assembly. When the coolant reaches the top of the fill hose, close the valve. This will eliminate air from the fill hose.
16. Close the valve on the venture assembly.
17. If there is a suspected leak in the cooling system, allow the system to stabilize under vacuum and monitor for vacuum loss. If vacuum loss is observed, refer to «Loss of Coolant»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
18. Open the valve on the vacuum gauge assembly. The vacuum gauge will drop as coolant is drawn into the system.
19. Once the vacuum gauge reaches zero, close the valve on the vacuum gauge assembly and repeat steps 11-17.
20. Remove the J 42401 radiator cap and surge tank test adapter.
21. Detach the Vac-N-Fill cap from the vehicles coolant fill port.
22. Add coolant to the system as necessary.
23. Inspect the concentration of the coolant mixture using J 26568 coolant and battery tester .
24. Detach the vacuum hose form the vacuum gauge assembly.
25. Attach the extraction hose to the vacuum hose.
26. Open the valve on the venture assembly to start a vacuum draw.
27. Use the extraction hose to draw out coolant to the proper level.
28. The vacuum tank has a drain valve on the bottom of the tank. Open the valve to drain coolant from the vacuum tank into a suitable container for disposal.

Flushing

Radiator Cleaning

An engine will overheat if the radiator has any of the following conditions

1. Leaks
2. Dirt or obstructions in the core

Use a soft bristle brush and clean hot water or a mild detergent solution in order to clean the outside of the radiator core. A car wash or dishwashing liquid is a suitable detergent.

A common city water hose may also be used in order to clean the outside of the radiator. Remove the nozzle from the hose prior to use in order to prevent damage to the fins.

Use one of the following solutions in order to pressure flush and clean the inside of the core tubes

1. Clean hot water
2. Mild car wash
3. Dishwashing liquid

Use the following steps in order to test the radiator for restrictions

1. Warm the engine.
2. Turn off the engine.
3. Feel the radiator. The radiator should be hot along the left side and warm along the right side. There should be an even temperature rise from right to left. Cold spots in the radiator indicate clogged sections.

J 38185 Hose Clamp Piers

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Recover the refrigerant. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/express-g3500/2013-2013/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) .
3. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
4. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
5. Remove the surge tank. Refer to «Radiator Surge Tank Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Remove the front grille. Refer to «Grille Replacement (Base)»(/chevrolet/express-g3500/2013-2013/remont/exteriorinterior-trim/#exterior-trim) , «Grille Replacement (Uplevel)»(/chevrolet/express-g3500/2013-2013/remont/exteriorinterior-trim/#exterior-trim) .
7. Remove the front bumper. Refer to «Front Bumper Replacement»(/chevrolet/express-g3500/2013-2013/remont/exterior-body-panels/#bumpers-and-fascias) .
8. Remove the charge air cooler inlet and outlet ducts. Refer to «Charge Air Cooler Inlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) , and «Charge Air Cooler Outlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
9. Using the J 38185 hose clamp piers , reposition the radiator inlet hose clamp.
10. Disconnect the radiator inlet hose from the thermostat housing.
11. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
12. Remove the radiator outlet hose to radiator retaining clip and disconnect the hose.
13. Remove the upper transmission cooler line to radiator retaining clip and disconnect the line.
14. Remove the transmission cooler line to auxiliary transmission cooler retaining clip and disconnect the line.
15. Remove the evaporator to condenser hose retaining nut (1).
16. Disconnect the evaporator to condenser hose from the condenser.
17. Remove the suction hose bolt (1) from the air conditioning (A/C) compressor.
18. Disconnect the suction hose (4) from the A/C compressor.
19. Disconnect the wiring ground located at the RH fender.
20. Remove the RH fender to core support brace bolts and remove the brace.
21. Disconnect the wiring ground located at the LH fender.
22. Remove the LH fender to core support brace bolts and remove the brace.
23. Disconnect the wiring harness electrical connector at the underhood bused electrical center (UBEC).
24. Disconnect the hood release cable at the hood release latch. Position the cable aside.
25. Remove the positive battery cable nut from the junction block and disconnect the cable.
26. Remove the auxiliary positive cable nut from the junction block and disconnect the cable.
27. Remove the positive battery to UBEC cable nut from the junction block and disconnect the cable.
28. Remove the 4 LH and 4 RH core support bolts (1).
29. Remove the core support and the cooling layer.

J 38185 Hose Clamp Pliers

1. Position the core support and the cooling layer to the vehicle.
2. Install the 4 LH and RH core support bolts (1) and tighten to 25 N.m (18 lb ft).
3. Position the positive battery to underhood bused electrical center (UBEC) cable to the junction block and install the nut then tighten to 8 N.m (71 lb in).
4. Position the auxiliary positive cable to the junction block and install the nut then tighten to 8 N.m (71 lb in).
5. Position the positive battery cable to the junction block and install the nut then tighten to 8 N.m (71 lb in).
6. Reposition and connect the hood release cable to the hood release latch.
7. Connect the wiring harness electrical connector at the UBEC.
8. Position the LH fender to core support brace and install the bolts.
9. Position the wiring ground to the LH fender and install the bolt and tighten to 9 N.m (80 lb in).
10. Position the RH fender to core support brace and install the bolts.
11. Position the wiring ground to the RH fender and install the bolt and tighten to 9 N.m (80 lb in).
12. Connect the suction hose (4) to the air conditioning (A/C) compressor.
13. Install the suction hose bolt (1) to the A/C compressor and tighten to 16 N.m (12 lb ft).
14. Position the evaporator to condenser hose to the condenser.
15. Install the evaporator to condenser hose nut (1) and tighten to 16 N.m (12 lb ft).
16. Position the transmission cooler line to the auxiliary transmission cooler and install the retaining clip.
17. Position the upper transmission cooler line to the radiator and install the retaining clip.
18. Lower the vehicle.
19. Position the radiator outlet hose to radiator and install the retaining clip.
20. Connect the radiator inlet hose to the radiator.
21. Using the J 38185 hose clamp pliers , reposition the radiator inlet hose clamp.
22. Install the charge air cooler inlet and outlet ducts. Refer to «Charge Air Cooler Inlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) , and «Charge Air Cooler Outlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
23. Install the front bumper. Refer to «Front Bumper Replacement»(/chevrolet/express-g3500/2013-2013/remont/exterior-body-panels/#bumpers-and-fascias) .
24. Install the front grille. Refer to «Grille Replacement (Base)»(/chevrolet/express-g3500/2013-2013/remont/exteriorinterior-trim/#exterior-trim) , «Grille Replacement (Uplevel)»(/chevrolet/express-g3500/2013-2013/remont/exteriorinterior-trim/#exterior-trim) .
25. Install the surge tank. Refer to «Radiator Surge Tank Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
26. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
27. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
28. Recharge the refrigerant. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/express-g3500/2013-2013/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) .
29. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Piers

Removal Procedure

1. Partially drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the overflow hose from the surge tank.
3. Using J 38185 hose clamp piers , reposition the surge tank inlet hose clamp.
4. Remove the surge tank inlet hose from the surge tank.
5. Using J 38185 hose clamp piers , reposition the surge tank outlet hose clamp.
6. Disconnect the surge tank outlet hose from the surge tank.
7. Remove the surge tank retaining bolt.
8. Tilt the surge tank assembly and disconnect the surge tank electrical connector.
9. Remove the surge tank from the vehicle.

Installation Procedure

1. Connect the surge tank electrical connector.
2. Install the surge tank to the vehicle.
3. Install the surge tank retaining bolt and tighten to 9 N.m (80 lb in).
4. Install the surge tank outlet hose to the surge tank.
5. Using J 38185 hose clamp piers , reposition the surge tank outlet hose clamp.
6. Install the surge tank inlet hose to the surge tank.
7. Using J 38185 hose clamp piers , reposition the surge tank inlet hose clamp.
8. Install the overflow hose to the surge tank.
9. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Partially drain the coolant. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Disconnect the hose from the coolant recovery reservoir.
3. Remove the coolant recovery reservoir retaining screws.
4. Remove the coolant recovery reservoir.

1. Install the coolant recovery reservoir.
2. Install the coolant recovery reservoir retaining screws and tighten to 6 N.m (53 lb in).
3. Connect the hose to the coolant recovery reservoir.
4. Add coolant to reservoir. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Partially drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using J 38185 hose clamp pliers reposition the surge tank inlet hose clamps.
3. Remove the surge tank inlet hose from the surge tank.
4. Remove the surge tank inlet hose from the radiator.

1. Install the surge tank inlet hose to the radiator.
2. Install the surge tank inlet hose to the surge tank.
3. Using J 38185 hose clamp pliers reposition the surge tank inlet hose clamp.
4. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Pliers

1. Partially drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
3. Reposition the clamp from the radiator inlet using the J 38185 hose pliers .
4. Reposition the clamp from the engine using the J 38185 hose pliers .
5. Remove the radiator inlet hose from the radiator.
6. Remove the radiator inlet hose from the engine.
7. Remove the radiator inlet hose (5).

1. Install the radiator inlet hose (5).
2. Install the radiator inlet hose to the radiator.
3. Install the radiator inlet hose to the engine.
4. Position the hose clamp from the engine using the J 38185 hose pliers.
5. Position the hose clamp from the radiator inlet engine using the J 38185 hose pliers .
6. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
7. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

Radiator Inlet Hose Replacement (LGH)

Special Tools

J-38185 Hose Clamp Pliers

For equivalent regional tools, refer to Special Tools .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
3. Remove the radiator inlet hose clamp (1) at engine using J-38185 pliers.
4. Remove the radiator inlet hose (2) from the engine.
5. Remove the radiator inlet hose clamp (1) at radiator using J-38185 pliers.
6. Remove the radiator inlet hose (2) from the radiator.
7. Remove the radiator inlet hose from the vehicle.

1. Install the radiator inlet hose to the vehicle.
2. Install the radiator inlet hose (2) to the radiator.
3. Install the radiator inlet hose clamp (1) at radiator using J-38185 pliers.
4. Install the radiator inlet hose (2) to the engine.
5. Install the radiator inlet hose clamp (1) at engine using J-38185 pliers.
6. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
7. Fill the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
2. Remove the clamp at the radiator outlet using the J 38185 hose clamp pliers.
3. Remove the radiator outlet hose clamp at the engine using the J 38185 hose clamp pliers .
4. Remove the radiator outlet hose clamp at the coolant recovery reservoir using the J 38185 hose clamp pliers.
5. Disconnect the radiator outlet hose from the radiator. Refer to «Radiator Hose Quick Connect Fitting»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Disconnect the radiator outlet hose from the engine.
7. Remove the radiator outlet hose (4) from the engine compartment.

1. Install the radiator outlet hose (4) into the engine compartment.
2. Connect the radiator outlet hose to the engine.
3. Connect the radiator outlet hose to the radiator. Refer to «Radiator Hose Quick Connect Fitting»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Install the radiator outlet hose to the coolant recovery reservoir.
5. Install the radiator outlet hose clamp to the coolant recovery reservoir using the J 38185 hose clamp pliers
6. Install the radiator outlet hose clamp to the engine using the J 38185 hose clamp pliers.
7. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

J-38185 Hose Clamp Pliers

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
2. Remove the clamp at the radiator outlet using the J-38185 hose clamp pliers.
3. Remove the radiator outlet hose clamp at the engine using the J-38185 hose clamp pliers.
4. Remove the radiator outlet hose clamp at the coolant recovery reservoir using the J-38185 hose clamp pliers.
5. Remove the radiator outlet hose from the coolant recovery reservoir.
6. Remove the radiator outlet hose from the radiator.
7. Remove the radiator outlet hose from the engine.
8. Remove the radiator outlet hose (4).

1. Install the radiator outlet hose (4).
2. Install the radiator outlet hose to the engine.
3. Install the radiator outlet hose to the radiator.
4. Install the radiator outlet hose to the coolant recovery reservoir.
5. Install the radiator outlet hose clamp to the coolant recovery reservoir using the J-38185 hose clamp pliers.
6. Install the radiator outlet hose clamp to the engine using the J-38185 hose clamp pliers.
7. Install the radiator outlet clamp to the radiator outlet using the J-38185 hose clamp pliers .
8. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

Radiator Outlet Hose Replacement (LGH)

Special Tools

J-38185 Hose Clamp Pliers

For equivalent regional tools, refer to Special Tools .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
3. Remove the heater hose from the radiator outlet hose.
4. Remove the radiator outlet hose clamp (1) at surge tank using J-38185 pliers.
5. Disconnect the quick connect fitting on the radiator outlet hose (2) at the radiator.
6. Remove the radiator outlet hose (3) from the radiator.
7. Remove the radiator outlet hose clamp (1) at engine.
8. Remove the radiator outlet hose retainer (2) from the vehicle.
9. Remove the radiator outlet hose (3) from the vehicle.

Scheme 2

1. Install the radiator outlet hose (3) to the vehicle.
2. Install the radiator outlet hose retainer (2) to the vehicle.
3. Install the radiator outlet hose clamp (1) at engine.
4. Install the radiator outlet hose (3) to the radiator.
5. Connect the quick connect fitting on the radiator outlet hose (2) at the radiator.
6. Install the radiator outlet hose clamp (1) at surge tank using J-38185 pliers.
7. Connect the heater hose to the radiator outlet hose.
8. Lower the vehicle.
9. Fill the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Using a bent-tip screwdriver or equivalent, pull on one of the open ends of the retaining ring in order to rotate the retaining ring.
2. Rotate the retaining ring (3) around the quick connector until the retaining ring is out of position and can be completely removed.
3. Remove the radiator outlet hose (2) from the quick connector fitting at the radiator (1).

1. Hook one of the open ends of the retaining ring (3) in one of the slots in the quick connector.
2. Rotate the retaining ring (3) around the connector until the retaining ring is positioned with all 3 ears through the 3 slots.
3. Ensure the 3 retaining ring ears can be seen from the inside of the connector and the retaining ring can move freely in the slots.
4. Install the radiator outlet hose (2) onto the radiator quick connector fitting until a click is heard or felt. Pull back on the radiator outlet hose (2) to ensure a proper connection.

1. Drain the coolant from the reservoir. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the vent hose from the throttle body.
4. Remove the vent hose from the radiator.
5. Remove the vent hose (1) from the vehicle.

1. Install the vent hose (1) to the vehicle.
2. Connect the vent hose to the radiator.
3. Connect the vent hose to the throttle body.
4. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Fill the reservoir with coolant. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Disengage the plastic caps from the quick connect fittings. Pull the caps back along the pipe.
2. Using a bent-tip screwdriver or equivalent, pull on one of the open ends of the retaining ring in order to rotate the retaining ring.
3. Rotate the retaining ring around the quick connector until the retaining ring is out of position and can be completely removed. Discard the retaining rings.
4. Remove the engine oil cooler line from the quick connector fitting at the radiator. Pull the lines straight out from the connectors.
5. Clean all of the components in a suitable solvent, and dry them with compressed air.
6. Inspect the fittings, the connectors, the cooler lines, and the cooler for damage, distortion, or restriction. Replace parts as necessary.

1. Install a new retaining ring into each quick connector fitting.
2. Hook one of the open ends of the retaining ring in one of the slots in the quick connector.
3. Rotate the retaining ring around the connector until the retaining ring is positioned with all 3 ears through the 3 slots.
4. Ensure the 3 retaining ring ears can be seen from the inside of the connector and the retaining ring can move freely in the slots.
5. Install the engine oil cooler line into the quick connector fitting until a click is heard or felt. Pull back on the engine oil cooler lines to ensure a proper connection.
6. Snap the plastic cap onto the quick connect fitting.
7. Ensure that the plastic cap is fully seated against the fitting.
8. Ensure that no gap is present between the cap and the fitting.
9. Inspect and fill the engine oil to the proper level.

1. Disconnect the oil cooler hose (1) from the radiator. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. Gently, pull the oil cooler pipe fittings straight out from the radiator quick connect fittings.
3. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information)
4. Remove the oil cooler hose bracket nut (1).
5. Remove the oil cooler hose adapter nut (2).
6. Remove the oil cooler hose assembly and seals.
7. Discard the seals.
8. Inspect the fittings, connectors and cooler hoses for damage or distortion.

1. Install the oil cooler hose assembly and a new seals.
2. Install the oil cooler hose adapter nut (2) and tighten to 12 N.m (106 lb in)
3. Install the oil cooler hose bracket nut (1) and tighten to 25 N.m (18 lb ft)
4. Connect the oil cooler hose (1) to the radiator. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
5. Pull back sharply on the cooler line in order to ensure that the cooler line is installed in the quick connect fitting.

The optional oil cooler is either an integral part of the radiator or a separate unit placed in front of the radiator. The cooler lines and hoses are serviceable.

1. Disconnect the cooler lines. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Open the oil cooler hose clip located on the lower fan shroud.
3. Remove the oil cooler hoses from the clip.
4. Gently, pull the oil cooler pipe fittings straight out from the radiator quick connect fittings.
5. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
6. Remove the oil cooler hose bracket bolt (1).
7. Remove the oil cooler hose adapter bolts (2).
8. Remove the oil cooler hose assembly and gasket.
9. Discard the gasket.
10. Inspect the fittings, connectors and cooler hoses for damage or distortion.

1. Install the oil cooler hose assembly and a new gasket.
2. Clean all dirt and oil from oil cooler hose adaptor bolt (2) threads and apply teftlon pipe sealant to the threads. Refer to «Adhesives, Fluids, Lubricants, and Sealers»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__adhesives-fluids-lubricants-and-sealers)
3. Install the oil cooler hose adapter bolts (2) and tighten to 12 N.m (106 lb in).
4. Install the oil cooler hose bracket bolt (1) and tighten to 25 N.m (18 lb ft).
5. Install the oil cooler hoses to the hose clip on the fan shroud.
6. Snap the oil cooler hose clip shut.
7. Connect the oil cooler lines. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Pull back sharply on the cooler line in order to ensure that the cooler line is installed in the quick connect fitting.

1. If a fan assembly fails, inspect the hub and the drive components. A fan assembly may fail due to an imbalance in the hub. This type of failure may not be the fault of the blades.
2. Remove the fan clutch assembly. Refer to «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the fan to fan clutch retaining bolts.
4. Remove the fan from the fan clutch.

1. Install the fan to the fan clutch.
2. Install the fan to fan clutch retaining bolts and tighten to 23 N.m (17 lb ft).
3. Install the fan clutch assembly. Refer to «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. J-41240-5A Fan Clutch Wrench
2. J-46406 Fan Clutch Remover and Installer

1. Remove the upper fan shroud. Refer to «Engine Coolant Fan Upper Shroud Replacement (4.3L, 4.8L, 5.3L, 6.0L, 6.2L, 7.0L)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Engine Coolant Fan Upper Shroud Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Install the J- 41240-5A fan clutch wrench onto the fan clutch nut. Install the J-46406 fan clutch remover and installer in order to secure the pulley.
3. Remove the fan clutch assembly.
4. Inspect the following components for cracks, distortion, or other damage: The belt The hub The adapter The pulley
5. Remove the cooling fan from the fan clutch. Refer to «Fan Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Install the cooling fan to the fan clutch. Refer to «Fan Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Install the fan clutch assembly to the pulley.
3. Install the J- 41240-5A fan clutch wrench onto the fan clutch nut and tighten to 56 (41 lb ft). Install the J-46406 fan clutch remover and installer in order to secure the pulley.
4. Install the upper fan shroud. Refer to «Engine Coolant Fan Upper Shroud Replacement (4.3L, 4.8L, 5.3L, 6.0L, 6.2L, 7.0L)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Engine Coolant Fan Upper Shroud Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the fan clutch. Refer to «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
3. Disconnect the camshaft position sensor connector.
4. Remove the cooling fan pulley bolts (2) and nuts (3).
5. Remove the cooling fan pulley (1) and the cooling fan pulley spacer (4).

1. Install the cooling fan pulley spacer (4) and the cooling fan pulley (1).
2. Install the cooling fan pulley bolts (2) and nuts (3).
3. Tighten the cooling fan pulley bolts (1) and nuts (2) in sequence to 50 N.m (37 lb ft).
4. Connect the camshaft position sensor connector.
5. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
6. Install the fan clutch. Refer to «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 3

Turbocharger Coolant Return Pipe Replacement

1. Remove the turbocharger. Refer to «Turbocharger Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
2. Remove the exhaust gas recirculation (EGR) valve cooler assembly. Refer to «Exhaust Gas Recirculation Valve Cooler Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the generator mounting bracket. Refer to «Generator Bracket Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
4. Remove the cooling fan clutch. Refer to «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Reposition the hose clamp and move the turbocharger coolant return hose (1) away from the turbocharger coolant return pipe (2).
6. Remove the turbocharger coolant return pipe retainer bolt (1).
7. Remove the turbocharger coolant return pipe retainer bolt (1) attached to the right front valve cover.
8. Remove the turbocharger coolant return pipe retainer bolt (1) on top of the engine.
9. Remove the turbocharger coolant return pipe (3) and hose (2) from the engine.
10. Replace any worn or damaged hoses.

1. Position the turbocharger coolant return pipe onto engine.
2. Install the turbocharger coolant return pipe retainer bolt (1). Tighten Tighten the bolt to 25 N.m (18 lb ft).
3. Install the turbocharger coolant return hose (1) onto the turbocharger coolant return pipe (2)
4. Install the turbocharger coolant return to the pipe retainer bolt (1) onto the right front valve cover. Tighten Tighten the bolt to 25 N.m (18 lb ft).
5. Install the turbocharger coolant return pipe retainer bolt (1). Tighten Tighten the bolt to 25 N.m (18 lb ft).
6. Install the turbocharger. Refer to «Turbocharger Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
7. Install the EGR valve cooler assembly. Refer to «Exhaust Gas Recirculation Valve Cooler Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the generator mounting bracket. Refer to «Generator Bracket Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
9. Install the cooling fan clutch. Refer to «Fan Clutch Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/express-g3500/2013-2013/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling) .
2. Drain the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the positive crankcase ventilation hose. Refer to «Positive Crankcase Ventilation Hose/Pipe/Tube Replacement (Oil Separator to Oil Pan)»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) , «Positive Crankcase Ventilation Hose/Pipe/Tube Replacement (Regulator Valve to Separator)»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
4. Compress the clamps (1) and disconnect the turbocharger coolant feed hose (2) from the turbocharger coolant feed pipes (3).
5. Remove the turbocharger coolant feed bolt (1) and washers (2), from the turbocharger.
6. Remove the turbocharger coolant feed pipe retainer bolt (3).
7. Remove the turbocharger coolant feed pipe (4).
8. Remove the turbocharger coolant feed pipe retainer bolt (1).
9. Slide the hose clamp (4) upward and remove the turbocharger coolant feed pipe (2) and hose (3) from the engine.
10. Slide the hose clamp (1) downward and remove the turbocharger coolant feed hose (3) from the turbocharger coolant feed pipe (2).

1. Position the turbocharger inlet cooling hose/pipe to the vehicle.
2. Using NEW brass seals (2), finger-tighten the turbocharger coolant feed pipe bolt (1) to the turbocharger.
3. Install the turbocharger coolant feed pipe retainer bolt (3) and tighten to 10 N.m (89 lb in).
4. Tighten the turbocharger coolant feed pipe bolt (1) to 25 N.m (18 lb ft).
5. Install the turbocharger coolant feed hose (2) to the turbocharger coolant feed pipes (3).
6. Slide the turbocharger coolant feed hose (3) onto the thermostat housing and secure with the hose clamps (4).
7. Install the turbocharger coolant feed pipe retainer bolt (1) and tighten to 10 N.m (89 lb in).
8. Fill the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/express-g3500/2013-2013/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling) .
10. Install the positive crankcase ventilation hose. Refer to «Positive Crankcase Ventilation Hose/Pipe/Tube Replacement (Oil Separator to Oil Pan)»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) , «Positive Crankcase Ventilation Hose/Pipe/Tube Replacement (Regulator Valve to Separator)»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the turbocharger air inlet adapter. Refer to «Turbocharger Air Inlet Adapter Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
3. Remove the intake manifold tube. Refer to «Intake Manifold Tube Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
4. Remove the exhaust gas recirculation valve temperature sensor - 1. Refer to «Exhaust Gas Recirculation Valve Temperature Sensor Replacement - Position 1»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
5. Disconnect both exhaust gas recirculation coolant hoses from the exhaust gas recirculation valve cooler.
6. If equipped, remove the exhaust outlet pipe heat shield bolts (3) and remove the exhaust outlet pipe heat shield (4).
7. Remove the exhaust outlet pipe to exhaust gas recirculation valve cooler fasteners (1).
8. Remove the rear exhaust gas recirculation valve cooler bolts (3).
9. Remove the front exhaust gas recirculation valve cooler bolt (1).
10. Disconnect the exhaust gas recirculation valve electrical connector (2).
11. Carefully remove the exhaust gas recirculation valve assembly (1) from the engine.
12. Remove the exhaust gas recirculation valve to exhaust gas recirculation valve cooler bolts (3).
13. Separate the exhaust gas recirculation valve cooler (1) from the exhaust gas recirculation valve (2).
14. Discard the gasket.

1. Connect the exhaust gas recirculation valve cooler (1) to the exhaust gas recirculation valve (2) using a NEW gasket.
2. Install the exhaust gas recirculation valve to exhaust gas recirculation valve cooler bolts (3) and tighten to 25 (18 lb ft).
3. Carefully Install the exhaust gas recirculation valve assembly (1) to the engine.
4. Connect the exhaust gas recirculation valve electrical connector (2).
5. Install the front exhaust gas recirculation valve cooler bolt (1) and tighten to 25 (18 lb ft).
6. Install the rear exhaust gas recirculation valve cooler bolts (3) and tighten to 50 (37 lb ft).
7. Install the exhaust outlet pipe to exhaust gas recirculation valve cooler fasteners (1) and tighten to 53 (39 lb ft).
8. If equipped, Install the exhaust outlet pipe heat shield (4), washers (2) and tighten the bolts to 10 (89 lb in).
9. Connect both exhaust gas recirculation coolant hoses from the exhaust gas recirculation valve cooler.
10. Install the exhaust gas recirculation valve temperature sensor - 1. Refer to «Exhaust Gas Recirculation Valve Temperature Sensor Replacement - Position 1»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
11. Install the intake manifold tube. Refer to «Intake Manifold Tube Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
12. Install the turbocharger air inlet adapter. Refer to «Turbocharger Air Inlet Adapter Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
13. Refill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 4

Exhaust Gas Recirculation Coolant Hoses/Pipes Replacement (LGH)

Note. The thermostat is not serviceable separately. The water pump inlet and thermostat must be replaced as an assembly.

1. Remove the bolt from the coolant recovery reservoir and reposition.
2. Remove air cleaner assembly.
3. Remove the radiator outlet hose. Refer to «Radiator Outlet Hose Replacement (LR4, LM7, LQ4)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the water pump inlet bolts.
5. Remove the water pump inlet and thermostat from the water pump.

1. Install the thermostat and water pump inlet to the water pump.
2. Install the water pump inlet bolts and tighten to 15 N.m (11 lb ft).
3. Install the radiator outlet hose. Refer to «Radiator Outlet Hose Replacement (LR4, LM7, LQ4)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Install the air cleaner assembly.
5. Install the coolant recovery reservoir and bolt and tighten to 11 N.m (97 lb in).

1. Remove the air cleaner and the duct assembly. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
2. Partially drain the coolant. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
3. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Disconnect the radiator hose from the thermostat housing.
5. Remove the bolts attaching the thermostat housing to the thermostat.
6. Remove the thermostat housing.
7. Remove the thermostat.
8. Clean the gasket mating surfaces.

1. Install the thermostat.
2. Install the thermostat housing to the intake manifold.
3. Install the bolts to the housing and tighten to 25 N.m (18 lb ft).
4. Connect the radiator hose to the thermostat housing.
5. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Install the air cleaner and the duct. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
7. Refill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
8. Bleed the air from the cooling system.
9. Inspect the thermostat housing and the gasket for coolant leaks.

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__radiator-inlet-hose-replacement-lgh) .
3. Remove the generator. Refer to «Generator Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
4. Disconnect the turbocharger coolant feed pipe retaining bracket bolt. Refer to «Turbocharger Coolant Hoses/Pipes Replacement (Feed - LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Turbocharger Coolant Hoses/Pipes Replacement (Return - LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Remove the fuel pressure valve bracket bolt (1) and reposition the fuel line (2).
6. Remove the thermostat bolts (1) from the engine coolant outlet pipe (2).
7. Remove thermostat (1) and thermostat (2) from the engine coolant thermostat housing.

Inspection Procedure

1. Inspect the thermostats for sticking, cracks, and/or leakage of wax.
2. Replace the thermostats if damage is found.
3. Clean the thermostat housing and thermostat housing cover sealing surfaces.

1. Install thermostat (1) and thermostat (2) with seals, to the thermostat housing.
2. Position the thermostat housing (2) and install the bolts (1). Tighten to 25 N.m (17 lb ft).
3. Connect the turbocharger coolant feed pipe retaining bracket bolt. Refer to «Turbocharger Coolant Hoses/Pipes Replacement (Feed - LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Turbocharger Coolant Hoses/Pipes Replacement (Return - LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Position the fuel pressure valve bolt (1) and fuel line (2) to the thermostat housing and tighten to 25 N.m (17 lb ft).
5. Install the generator. Refer to «Generator Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
6. Compress the clamp and connect the radiator inlet hose to the thermostat housing.
7. Fill the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the radiator fan. Refer to «Fan Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__radiator-inlet-hose-replacement-lgh) .
3. Remove the fuel return canister from the clip retainer at the top of the thermostat housing.
4. Remove the drive belt tensioner. Refer to «Drive Belt Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
5. Remove the generator bracket. Refer to «Generator Bracket Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
6. Remove the air conditioning (A/C) compressor bracket. Refer to «Air Conditioning Compressor Bracket Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Remove the fuel pressure valve bolt (1) and reposition the fuel line (2).
8. Disconnect the engine coolant temperature sensor electrical connector (1).
9. Remove the turbocharger coolant feed hose (2).
10. Remove the oil fill tube bolt (3), the oil fill tube retainer bracket bolt (4), and the oil fill tube (5).
11. Disconnect the turbocharger coolant return hose (1) at the thermostat bypass pipe (3).
12. Remove the thermostat bypass bolts (2) at the water pump and remove the thermostat bypass pipe (3).
13. Remove the thermostat housing crossover bolts (1) and nuts (2).
14. Remove the thermostat housing crossover pipe (4) and gaskets (3).

1. Position the thermostat housing crossover with NEW gaskets.
2. Install the thermostat housing crossover bolts (1) and nuts (2).Tighten to 25 N.m (18 lb ft).
3. Install the thermostat bypass bolts (2) to the water pump and tighten to 21 N.m (16 lb ft).
4. Connect the turbocharger coolant return hose (1) to the thermostat bypass pipe (3).
5. Install the oil fill tube bolt (3) and tighten to 25 N.m (18 lb ft).
6. Install the oil fill tube bracket bolt (4) and tighten to 25 N.m (18 lb ft).
7. Install the turbocharger coolant feed hose (2) and the engine coolant temperature sensor connector (1).
8. Install the fuel return line canister into the clip retainer at the top of the thermostat housing.
9. Install the fuel pressure valve bolt (1) and tighten to 25 N.m (18 lb ft).
10. Install the A/C compressor bracket. Refer to «Air Conditioning Compressor Bracket Replacement (Diesel)»(/chevrolet/express-g3500/2013-2013/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) .
11. Install the generator bracket. Refer to «Generator Bracket Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
12. Install the drive belt tensioner. Refer to «Drive Belt Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
13. Install the radiator fan. Refer to «Fan Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
14. Install the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__radiator-inlet-hose-replacement-lgh) .

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .
2. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
3. Reposition the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
4. Remove the radiator vent inlet hose (2) from the coolant air bleed pipe fitting.
5. Remove the coolant air bleed pipe bolts (309) (intake manifold shown removed for clarity).
6. Remove the coolant air bleed pipe (307) and seals (308).
7. Remove the coolant air bleed cover bolts (312), if required.
8. Remove the coolant air bleed covers (313) and seals (308), if required.
9. Remove the seals (308) from the coolant air bleed pipe and/or covers.
10. Discard the seals.

1. Install the seals onto the coolant air bleed pipe and/or covers.
2. Install the coolant air bleed pipe (307) and seals (308) onto the cylinder heads.
3. Install the coolant air bleed pipe bolts (309) and tighten to 12 N.m (106 lb in).
4. Install the coolant air bleed covers (313) and seals (308), if required.
5. Install the coolant air bleed cover bolts (312), if required and tighten to 12 N.m (106 lb in).
6. Install the radiator vent inlet hose (2) to the coolant air bleed pipe fitting.
7. Position the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
8. Install the air cleaner outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .
9. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .
2. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
3. Reposition the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
4. Remove the radiator vent inlet hose (2) from the coolant air bleed pipe fitting.
5. Remove the coolant air bleed pipe bolts (309) (intake manifold shown removed for clarity).
6. Remove the coolant air bleed pipe (307) and seals (308).
7. Remove the coolant air bleed cover bolts (312), if required.
8. Remove the coolant air bleed covers (313) and seals (308), if required.
9. Remove the seals (308) from the coolant air bleed pipe and/or covers.
10. Discard the seals.

1. Install the seals onto the coolant air bleed pipe and/or covers.
2. Install the coolant air bleed pipe (307) and seals (308) onto the cylinder heads.
3. Install the coolant air bleed pipe bolts (309) and tighten to 12 N.m (106 lb in).
4. Install the coolant air bleed covers (313) and seals (308), if required.
5. Install the coolant air bleed cover bolts (312), if required and tighten to 12 N.m (106 lb in).
6. Install the radiator vent inlet hose (2) to the coolant air bleed pipe fitting.
7. Position the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
8. Install the air cleaner outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .
9. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

Scheme 5

Thermostat Bypass Pipe Replacement (LGH)

J 41240 Fan Clutch Remover and Installer

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
2. Remove the air cleaner outlet resonator duct. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
3. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
4. Remove the cooling fan.
5. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
6. Reposition the radiator outlet hose clamps at the surge tank and water pump.
7. Remove the radiator outlet hose from the surge tank.
8. Remove the radiator outlet hose from the water pump.
9. Reposition the water pump inlet hose clamps.
10. Remove the water pump inlet hose.
11. Using J 41240 fan clutch remover and installer to hold the water pump pulley, remove the water pump pulley bolts.
12. Remove the water pump bolts.
13. Remove the water pump.
14. Remove and discard the water pump gaskets.
15. Clean and inspect the water pump, if necessary. Refer to «Water Pump Cleaning and Inspection»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3__water-pump-cleaning-and-inspection) .

1. If reusing the fasteners, apply sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent to the threads of the water pump bolts.
2. Install NEW water pump gaskets and the water pump. CAUTION: Refer to «Fastener Caution»(/chevrolet/express-g3500/2013-2013/remont/oem-general-information/#dangers-warnings-and-cautions__fastener-caution) .
3. Install the water pump bolts and tighten to 45 N.m (33 lb ft).
4. Using J 41240 fan clutch remover and installer to hold the water pump pulley, install the water pump pulley bolts and tighten to 25 N.m (18 lb ft).
5. Install the water pump inlet hose.
6. Position the water pump inlet hose clamps.
7. Install the radiator outlet hose to the water pump.
8. Install the radiator outlet hose to the surge tank.
9. Position the radiator outlet hose clamps at the surge tank and water pump.
10. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
11. Install the cooling fan.
12. Install the air cleaner outlet resonator duct. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
13. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) .
14. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
15. Inspect the cooling system for leaks.

1. Remove the air cleaner outlet assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .
2. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
3. Reposition the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
4. Remove the radiator vent inlet hose (2) from the coolant air bleed pipe fitting.
5. Reposition the radiator inlet hose clamp (3) at the water pump.
6. Remove the radiator inlet hose from the water pump.
7. Reposition the radiator inlet hose and vent inlet hose out of the way.
8. Remove the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) .
9. Reposition the radiator outlet hose clamp at the water pump.
10. Remove the radiator outlet hose from the water pump.
11. Reposition the outlet hose out of the way.
12. Reposition the radiator surge tank outlet hose clamp (1) at the water pump.
13. Remove the radiator surge tank outlet hose (2) from the water pump.
14. Reposition the outlet hose out of the way.
15. Reposition the heater inlet hose clamp (1) at the water pump.
16. Remove the heater inlet hose (2) from the water pump.
17. Reposition the inlet hose out of the way.
18. Remove the water pump bolts (301).
19. Remove the water pump (300) and gaskets (309). Discard the gaskets.

Note. All gaskets surfaces are to be free of oil or other foreign material during assembly.

1. Position the water pump (300) and NEW gaskets (306) to the engine block.
2. Install the water pump bolts (301). Tighten the bolts a first pass to 15 N.m (11 lb ft). Tighten the bolts a final pass to 30 N.m (22 lb ft).
3. Position and install the heater inlet hose (2) to the water pump.
4. Position the heater inlet hose clamp (1) at the water pump.
5. Position and install the radiator surge tank outlet hose (2) to the water pump.
6. Position the radiator surge tank outlet hose clamp (1) at the water pump.
7. Position and install the radiator outlet hose to the water pump.
8. Position the radiator outlet hose clamp at the water pump.
9. Install the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) .
10. Position the radiator inlet hose and vent inlet hose to the correct position.
11. Install the radiator inlet hose to the water pump.
12. Position the radiator inlet hose clamp (3) at the water pump.
13. Install the radiator vent inlet hose (2) to the coolant air bleed pipe fitting.
14. Position the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
15. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
16. Install the air cleaner outlet assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .

1. Remove the air cleaner outlet assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .
2. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
3. Reposition the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
4. Remove the radiator vent inlet hose (2) from the coolant air bleed pipe fitting.
5. Reposition the radiator inlet hose clamp (3) at the water pump.
6. Remove the radiator inlet hose from the water pump.
7. Reposition the radiator inlet hose and vent inlet hose out of the way.
8. Remove the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) .
9. Reposition the radiator outlet hose clamp at the water pump.
10. Remove the radiator outlet hose from the water pump.
11. Reposition the outlet hose out of the way.
12. Reposition the radiator surge tank outlet hose clamp at the water pump (1).
13. Remove the radiator surge tank outlet hose (2) from the water pump.
14. Reposition the outlet hose out of the way.
15. Reposition the heater inlet hose clamp (1) at the water pump.
16. Remove the heater inlet hose (2) from the water pump.
17. Reposition the inlet hose out of the way.
18. Remove the water pump bolts (301).
19. Remove the water pump (300) and gaskets (309). Discard the gaskets.

Note. All gaskets surfaces are to be free of oil or other foreign material during assembly.

1. Inspect the drained coolant for sand or other debris, flush the system as needed. Refer to «Flushing»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .
2. Inspect and clear the radiator vent hose fitting, if necessary. There is a small 2.0 mm (0.080 in) orifice (vent hose fitting) in the neck of the radiator where the coolant vent hose from the engine attaches to the radiator.
3. Position the water pump (300) and NEW gaskets (306) to the engine block.
4. Install the water pump bolts (301). Tighten the bolts a first pass to 15 N.m (11 lb ft). Tighten the bolts a final pass to 30 N.m (22 lb ft).
5. Position and install the heater inlet hose (2) to the water pump.
6. Position the heater inlet hose clamp (1) at the water pump.
7. Position and install the radiator surge tank outlet hose (2) to the water pump.
8. Position the radiator surge tank outlet hose clamp at the water pump (1).
9. Position and install the radiator outlet hose to the water pump.
10. Position the radiator outlet hose clamp at the water pump.
11. Install the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) .
12. Position the radiator inlet hose and vent inlet hose to the correct position.
13. Install the radiator inlet hose to the water pump.
14. Position the radiator inlet hose clamp (3) at the water pump.
15. Install the radiator vent inlet hose (2) to the coolant air bleed pipe fitting.
16. Position the radiator vent inlet hose clamp (1) at the coolant air bleed pipe fitting.
17. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
18. Install the air cleaner outlet assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system)
2. Remove the radiator outlet pipe. Refer to «Radiator Outlet Hose Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__radiator-outlet-hose-replacement-lgh)
3. Remove the thermostat bypass pipe. Refer to «Thermostat Bypass Pipe Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle__crankshaft-balancer-replacement) .
5. Remove the water pump to water pump outlet pipe nuts (1) from the studs (2).
6. Remove the water pump nut (1) and bolts (2).
7. Remove the water pump (5).
8. Remove and discard the water pump O-ring (3) and the water pump outlet pipe gasket (4).

1. Lubricate the water pump O-ring (3) with engine oil.
2. Install the water pump outlet pipe gasket (4) and the lubricated water pump O-ring (3).
3. Install the water pump nut (1) and bolts (2). Ensure the correct length bolt is used in the proper location and tighten to 25 N.m (18 lb ft).
4. Install the water pump to water pump outlet pipe nuts (1) to the studs (2) and tighten to 25 N.m (18 lb ft).
5. Install the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle__crankshaft-balancer-replacement) .
6. Install the thermostat bypass pipe. Refer to «Thermostat Bypass Pipe Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Install the radiator outlet pipe. Refer to «Radiator Outlet Hose Replacement (LGH)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__radiator-outlet-hose-replacement-lgh)
8. Perform the crankshaft position reluctor wheel learn procedure. Refer to «Crankshaft Position Reluctor Wheel Learn»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
2. Remove the positive crankcase ventilation pipe bracket bolt (5).
3. Remove the positive crankcase ventilation pipe bolt (4) and reposition the pipe (6).
4. Remove the water pump to water pump outlet pipe nuts (1) from the studs (2).
5. Remove the water pump to water pump outlet pipe studs (2) and discard the gasket (3).
6. Remove the five oil filter adapter and oil cooler assembly bolts (1) and the water pump outlet pipe (3).
7. Remove the water pump outlet pipe (1) from the oil filter adapter and oil cooler assembly (3).

1. Install a NEW water pump outlet pipe O-ring (2) onto the pipe and lubricate the O-ring seal with engine coolant.
2. Install new O-rings (2) to the oil filter adapter and oil cooler assembly. Lubricate the O-rings with engine oil.
3. Apply sealer to the O-ring sealing area (1). Refer to «Adhesives, Fluids, Lubricants, and Sealers»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-specifications__adhesives-fluids-lubricants-and-sealers)
4. Install the oil cooler assembly (2) and the water pump outlet pipe (3), to the engine block. Tighten the bolts (1) to 25 N.m (18 lb ft).
5. Position a NEW water pump outlet pipe gasket (3) to the water pump. Install the water pump outlet pipe to the water pump outlet pipe studs (1) and tighten the nuts (1) to 25 N.m (18 lb ft).
6. Install the positive crankcase ventilation pipe (6) with bolt (4) and the retainer bracket bolt (5). Tighten to 12 N.m (106 lb in).
7. Lower the vehicle.

Scheme 6

Engine Coolant Temperature Sensor Replacement

1. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) , for the 4.3L engine or «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) for the 4.8L, 5.3L, 6.0L, 6.2L, and 7.0L engines.
3. Remove the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) , for the 4.3L engine or «Air Cleaner Resonator Outlet Duct Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) for the 4.8L, 5.3L, 6.0L, 6.2L, and 7.0L engines.
4. For the 4.3L engine, remove the air conditioning (A/C) suction hose. Refer to «Suction Hose Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/express-g3500/2013-2013/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) for the 4.3L engine.
5. For the 4.8L, 5.3L and 6.0L engine, remove the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LU3, LR4, LM7, LQ4)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Remove the battery cable from the fan shroud clips and reposition.
7. Remove the mass air flow (MAF) sensor wire from the fan shroud clip and reposition.
8. Remove the transmission oil lever indicator.
9. Remove the fan shroud bolts (1, 3, 4).
10. Remove the fan shroud (2, 5).

1. Install the fan shroud (2, 5).
2. Install the fan shroud bolts (1, 3, 4) and tighten to 6 N.m (53 lb in).
3. Install the transmission oil lever indicator.
4. Install the MAF sensor wire to the fan shroud clip.
5. Install the battery cable to the fan shroud clips.
6. For the 4.3L engine, install the A/C suction hose. Refer to «Suction Hose Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/express-g3500/2013-2013/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) for the 4.3L engine.
7. For the 4.8L, 5.3L and 6.0L engine, install the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LU3, LR4, LM7, LQ4)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) , for the 4.3L engine or «Air Cleaner Resonator Outlet Duct Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) for the 4.8L, 5.3L, 6.0L, 6.2L, and 7.0L engines.
9. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) , for the 4.8L, 5.3L, 6.0L, 6.2L, and 7.0L engines or «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) for the 4.3L engine.
10. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the surge tank. Refer to «Radiator Surge Tank Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the charge air cooler inlet and outlet hoses. Refer to «Charge Air Cooler Inlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) , and «Charge Air Cooler Outlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
3. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
4. Disconnect the fan clutch electrical connector, if equipped.
5. Remove the intake air heater. Refer to «Intake Air Heater Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
6. Disconnect the cross car harness at buss bar on right core support.
7. Position cross car harness out of way.
8. Remove the transmission oil indicator.
9. Remove the engine oil indicator.
10. Remove the engine oil fill cap.
11. Remove the 2 upper fan shroud to core support bolts.
12. Remove the fan clutch electrical wiring harness routing clip, if equipped.
13. Remove the 4 upper fan shroud to lower fan shroud bolts.
14. Remove the upper fan shroud, while positioning the upper radiator hose.

1. Position the upper fan shroud in the vehicle, while positioning the upper radiator hose.
2. Install the 4 upper fan shroud to lower fan shroud bolts and tighten to 6 N.m (53 lb in).
3. Install the fan clutch electrical wiring harness routing clip, if equipped.
4. Install the 2 upper fan shroud to core support bolts and tighten to 6 N.m (53 lb in).
5. Install the engine oil fill cap.
6. Install the engine oil indicator.
7. Install the transmission oil indicator.
8. Position back cross car harness.
9. Connect the cross car harness on buss bar at right core support.
10. Install the intake air heater. Refer to «Intake Air Heater Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
11. Connect the fan clutch electrical connector, if equipped.
12. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
13. Install the charge air cooler inlet and outlet hoses. Refer to «Charge Air Cooler Inlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) , and «Charge Air Cooler Outlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
14. Install the surge tank. Refer to «Radiator Surge Tank Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) , for the 4.8L, 5.3L, 6.0L, 6.2L, 7.0L engines or «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) for the 4.3L engine.
3. Remove the fan shroud bolts (1,3,4).
4. Remove the fan shroud (2,5).

1. Install the fan shroud (2,5).
2. Install the fan shroud bolts (1,3,4) and tighten to 6 N.m (53 lb in).
3. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) , for the 4.8L, 5.3L, 6.0L, 6.2L, 7.0L engines or «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) for the 4.3L engine.
4. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
2. Remove the upper fan shroud to lower fan shroud retaining bolts.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
4. Remove the lower fan shroud retaining bolts.
5. Remove the lower fan shroud from the vehicle.

1. Install the lower fan shroud to the vehicle.
2. Install the lower fan shroud retaining bolts and tighten to 6 N.m (53 lb in).
3. Lower the vehicle.
4. Install the upper fan shroud to lower fan shroud retaining bolts and tighten to 6 N.m (53 lb in).
5. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .

1. J 38185 Hose Clamp Pliers
2. J 39529 Wiper Linkage Installer

Note. Always install a new set of insulators when replacing a radiator. Used insulators may be worn or too large for the new radiator. These conditions may cause the new radiator to be loose.

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) , for the 4.8L, 5.3L, 6.0L, 6.2L, 7.0L engines or «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) for the 4.3L engine.
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the clamp at the radiator inlet using the J 38185 hose clamp pliers.
4. Remove the radiator inlet hose (5) from the radiator.
5. Remove the outlet heater hose clamp at the radiator using the J 38185 hose clamp pliers.
6. Remove the outlet heater hose (2) from the radiator.
7. Remove the automatic transmission cooler lines. Refer to «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (4L60-E/4L65-E/4L70-E)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) , «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (6L45/6L50/6L80/6L90)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) .
8. Remove the engine oil cooler lines. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Remove the fan shroud bolts (1) from the top of the radiator support.
10. Remove the fan shroud bolts (3) from the sides of the fan shroud.
11. Remove the radiator (2).
12. Remove the radiator insulators (1, 3).
13. Inspect the following components: The radiator The insulators The hoses and clamps The mounting hardware Replace the components as necessary.

1. Install the radiator insulators (1, 3).
2. Install the radiator (2).
3. Install the fan shroud bolts (1) to the top of the radiator support and tighten to 6 N.m (53 lb in).
4. Install the fan shroud bolts (3) to the sides of the fan shroud and tighten to 6 N.m (53 lb in).
5. Install the engine oil cooler lines. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Install the automatic transmission oil cooler lines. Refer to «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (4L60-E/4L65-E/4L70-E)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) , «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (6L45/6L50/6L80/6L90)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) .
7. Install the radiator inlet hose (5) to the radiator.
8. Install the hose clamp at the radiator inlet housing using the J 38185 hose clamp pliers.
9. Install the outlet heater hose (2).
10. Install the outlet heater hose clamp using the J 39529 Wiper Linkage Installer.
11. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
12. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) , for the 4.8L, 5.3L, 6.0L, 6.2L, 7.0L engines or «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) for the 4.3L engine.
13. Inspect the automatic transmission fluid level. Refer to «Approximate Fluid Capacities»(/chevrolet/express-g3500/2013-2013/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .
14. Inspect the engine oil level. Refer to «Approximate Fluid Capacities»(/chevrolet/express-g3500/2013-2013/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .

1. J-38185 Hose Clamp Pliers
2. J-39529 Wiper Linkage Installer

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
2. Remove the upper radiator baffle.
3. Remove the surge tank. Refer to «Radiator Surge Tank Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove battery. Refer to «Battery Replacement (Primary)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
5. Remove the charged air cooler inlet pipe. Refer to «Charge Air Cooler Inlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
6. Remove the clamp at the radiator inlet using the J-38185 hose clamp pliers.
7. Remove the radiator inlet hose (5) from the radiator.
8. Remove the outlet heater hose clamp at the radiator using the J-38185 hose clamp pliers.
9. Remove the outlet heater hose (2) from the radiator.
10. Remove the automatic transmission cooler lines. Refer to «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (4L60-E/4L65-E/4L70-E)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) , «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (6L45/6L50/6L80/6L90)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) .
11. Remove the engine oil cooler lines. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
12. Remove the engine oil fill tube.
13. Remove intake manifold tube. Refer to «Intake Manifold Tube Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
14. Remove the upper radiator baffle. Remove the fan shroud bolts (1) from the top of the radiator support.
15. Remove the fan shroud bolts (3) from the sides of the fan shroud.
16. Remove the radiator mounting bolts from the charged air cooler.
17. Remove the charge air cooler bolts to core support.
18. Remove the radiator and charge air cooler as assembly.
19. Remove radiator bolts to charge air cooler.
20. Remove the radiator insulators.
21. Inspect the following components: The radiator The insulators The hoses and clamps The mounting hardware Replace the components as necessary.

1. Install the radiator insulators.
2. Install the radiator to the charge air cooler and tighten the bolts to 6 (53 lb in).
3. Install the radiator and charge air cooler as an assembly.
4. Install the radiator mounting bolts to the charged air cooler and tighten to 6 (53 lb in).
5. Install the fan shroud bolts (1) to the top of the radiator support and tighten to 6 (53 lb in).
6. Install the fan shroud bolts (3) to the sides of the fan shroud and tighten to 6 (53 lb in).
7. Install the engine oil cooler lines. Refer to «Engine Oil Cooler Pipe/Hose Quick Connect Fitting Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the automatic transmission oil cooler lines. Refer to «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (4L60-E/4L65-E/4L70-E)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) , «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (6L45/6L50/6L80/6L90)»(/chevrolet/express-g3500/2013-2013/remont/automatic-trans/#automatic-transmission-cooling-system) .
9. Install the radiator inlet hose (5) to the radiator.
10. Install the hose clamp at the radiator inlet housing using the J-38185 hose clamp pliers.
11. Install the outlet heater hose (2).
12. Install the outlet heater hose clamp using the J-39529 wiper linkage installer.
13. Install the intake manifold tube. Refer to «Intake Manifold Tube Replacement»(/chevrolet/express-g3500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
14. Install oil fill tube.
15. Install the upper radiator baffle.
16. Install the battery. Refer to «Battery Replacement (Primary)»(/chevrolet/express-g3500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
17. Install the charged air cooler pipe. Refer to «Charge Air Cooler Inlet Pipe Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
18. Install the surge tank assembly. Refer to «Radiator Surge Tank Replacement»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
19. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g3500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
20. Install the upper radiator baffle.
21. Inspect the automatic transmission fluid level. Refer to «Approximate Fluid Capacities»(/chevrolet/express-g3500/2013-2013/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .
22. Inspect the engine oil level. Refer to «Approximate Fluid Capacities»(/chevrolet/express-g3500/2013-2013/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
2. Disconnect the heater cord from the coolant heater (4).
3. Loosen the coolant heater bolt.
4. Remove the coolant heater from the engine block.
5. Do not score the machined surface of the hole.
6. Grasp the plug with pliers.
7. Pull the plug from the engine block.
8. Clean the core plug hole in order to remove the following substances: Burrs Compound Paint Rough spots

1. Coat the O-ring seal and the cleaned surface of the plug opening with water resistant high-temperature grease lubricant GM P/N 9985164 (Canadian P/N 10953480), or the equivalent.
2. Tightly push the coolant heater (1) into the engine block.
3. Tighten the coolant heater bolt until both of the locking wings draw tightly against the inner wall of the engine block and tighten to 2 N.m (18 lb in).
4. Connect the heater cord to the coolant heater (4).
5. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
6. Inspect the cooling system for leaks.

1. Drain the cooling system/engine block. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
3. For vehicles with regular production option (RPO) L76 (6.0L), perform the following steps. Otherwise, proceed to step 8.
4. Remove the oil cooler hose bracket bolt (1), if equipped.
5. Remove the oil cooler hose adapter bolts (2), if equipped.
6. Remove and discard the oil cooler hose adapter gasket, if equipped.
7. Position the oil cooler hose adapter end out of the way, if equipped.
8. Disconnect the coolant heater cord electrical connector (1).
9. Remove the coolant heater from the engine block.
10. Remove any burrs, sealer, or other rough spots.

1. If reusing the old coolant heater, apply thread sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent to the threads.
2. Install the coolant heater to the engine block and tighten to 50 N.m (37 lb ft).
3. Connect the coolant heater cord electrical connector (1).
4. For vehicles with RPO L76 (6.0L) perform the following steps otherwise proceed to step 10.
5. Position the oil cooler hose adapter end, if equipped.
6. Install a NEW oil cooler hose adapter gasket, if equipped.
7. Install the oil cooler hose adapter bolts (2), if equipped and tighten to 12 N.m (106 lb in).
8. Install the oil cooler hose bracket bolt (1), if equipped and tighten to 25 N.m (18 lb ft).
9. Lower the vehicle.
10. Fill the cooling system/engine block. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
2. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
3. Disconnect the coolant heater electrical connector (2).
4. Remove the coolant heater from the engine block.
5. Remove any burrs, sealer, paint or other rough spots.

1. If re-using the old coolant heater, apply thread sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent to the threads.
2. Install the coolant heater to the engine block and tighten to 50 N.m (37 lb ft).
3. Connect the coolant heater electrical connector (2).
4. Lower the vehicle.
5. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) , «Cooling System Draining and Filling (Static Fill Diesel)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the right front tire and wheel. Refer to «Tire and Wheel Removal and Installation (6-Lug Wheel)»(/chevrolet/express-g3500/2013-2013/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) , «Tire and Wheel Removal and Installation (8-Lug Wheel)»(/chevrolet/express-g3500/2013-2013/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) .
3. Disconnect the engine coolant heater cord.
4. Loosen the coolant heater bolt.
5. Remove the engine coolant heater from the engine block.
6. Do not score the machined surface of the hole.
7. Grasp the plug with pliers.
8. Pull the plug from the engine block.
9. Clean the core plug hole in order to remove the following substances: Burrs Compound Paint Rough spots

1. Coat the O-ring seal and the cleaned surface of the plug opening with water resistant high-temperature grease lubricant GM P/N 1052196 (Canadian P/N 5264008), or the equivalent.
2. Align the coolant heater element to point towards the top of the engine.
3. Tightly push the coolant heater into the engine block.
4. Tighten the bolt on the engine coolant heater until both of the locking wings draw tightly against the inner wall of the engine block and tighten to 2 N.m (18 lb in).
5. Connect the heater cord to the coolant heater.
6. Install the right front tire and wheel. Refer to «Tire and Wheel Removal and Installation (6-Lug Wheel)»(/chevrolet/express-g3500/2013-2013/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) , «Tire and Wheel Removal and Installation (8-Lug Wheel)»(/chevrolet/express-g3500/2013-2013/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) .
7. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/express-g3500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
8. Inspect for coolant leaks.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
2. Disconnect the coolant heater electrical connector (1).
3. Remove the coolant heater cord retainer (1).
4. Remove the coolant heater cord retainers (1).
5. Remove the coolant heater cord.

1. Install the coolant heater cord.
2. Install the coolant heater cord retainer (1).
3. Install the coolant heater cord retainers (1).
4. Connect the coolant heater electrical connector (1).
5. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
2. Disconnect the coolant heater electrical connector (1).
3. Remove the coolant heater cord retainers (1).
4. Remove the coolant heater cord.

1. Install the coolant heater cord.
2. Install the coolant heater cord retainers (1).
3. Connect the coolant heater electrical connector (1).
4. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g3500/2013-2013/remont/hoistjack/#general-information) .
2. Disconnect the coolant heater electrical connector (1).
3. Remove the coolant heater cord retainer (1).
4. Remove the coolant heater cord retainer (1).
5. Remove the coolant heater cord retainer (1).
6. Remove the coolant heater cord.

1. Install the coolant heater cord.
2. Install the coolant heater cord retainer (1).
3. Install the coolant heater cord retainer (1).
4. Install the coolant heater cord retainer (1).
5. Connect the coolant heater electrical connector (1).
6. Lower the vehicle.

Cooling Fan Control

The purpose of the electro-viscous (EV) fan clutch is to maintain powertrain cooling requirements. The engine control module (ECM) monitors the following sensors to regulate the fan speed

1. Engine coolant temperature
2. A/C refrigerant pressure
3. Vehicle speed
4. Intake air temperature
5. Transmission fluid temperature
6. Ambient air temperature
7. Cooling fan speed

The EV cooling fan clutch system enables the engine control module (ECM) to change the speed of the pulley driven cooling fan in relation to the engine speed. Ignition voltage is supplied directly to the fan clutch solenoid valve. The ECM uses two output drivers and a parallel circuit to directly control the EV fan clutch solenoid valve. The ECM controls the solenoid valve by pulse width modulating (PWM) the parallel control circuits to ground, with a solid state device called a driver. The ECM changes the cooling fan speed by increasing or decreasing the solenoid valve ON time, known as duty cycle. As the ECM command increases, so does the ON time of the solenoid. When the solenoid in the fan clutch is energized, it opens the spring loaded valve and allows fluid to flow from the storage chamber to the fluid coupling of the cooling fan clutch, increasing the fan speed. When the solenoid is de-energized, the spring loaded valve closes, and allows the fluid in the coupling of the fan clutch to drain back to the storage chamber, reducing fan speed. The rapid modulation of the fan clutch solenoid valve gives the ECM the ability to precisely control the amount of fluid that remains in the fluid coupler, allowing more effective regulation of the fan speed and powertrain cooling requirements.

The fan clutch supplies a feedback signal to the ECM, as an actual fan speed input. The fan speed sensor is a hall effect sensor which is internal to the fan clutch. The ECM supplies a 5-volt reference and a low reference to the hall effect sensor. The hall effect sensor returns a signal pulse through the cooling fan speed signal circuit in response to the reluctor track passing by the magnetic field of the hall effect sensor.

The scan tool can operate the cooling fan clutch. This is done through the controls function menu screen. Cooling fan clutch engagement can take up to 2 minutes with a 100 percent command and the engine speed at 2,000 RPM. The lower the engine speed, the longer it will take for the fan to engage. Cooling fan disengagement can take up to 2 minutes with the engine speed at 2,000 RPM. The lower the engine speed, the longer it will take to disengage. In lower ambient air temperatures the cooling fan will engage in less time, however, it will take longer to disengage due to the properties of the fluid vs. temperature.

Under certain conditions the cooling fan may be engaged at engine start. The cooling may have been engaged at the time the engine was turned off. Or, fluid may bleed from the storage chamber into the fluid coupling of the cooling fan clutch while the engine is off. Although the fan clutch is commanded off during a cold start, this is the most likely time a vehicle driver will notice that the fan noise is excessive in comparison to engine starts when the fan clutch is disengaged.

Coolant Heater

The optional engine coolant heater (RPO KO5) is designed to warm the coolant in the engine block area for improved starting in very cold weather (temperatures below -29°C (-20°F). The coolant heater helps reduce fuel consumption when a cold engine is warming up. The engine coolant heater operates using AC external power and a heating element installed in the water jacket of the engine block. The heating element warms the coolant when the heater cord is plugged into an AC power source.

The unit is equipped with a detachable AC power cord. A weather shield on the cord is provided to protect the plug when not in use.

The cooling systems function is to maintain an efficient engine operating temperature during all engine speeds and operating conditions. The cooling system is designed to remove approximately one-third of the heat produced by the burning of the air-fuel mixture. When the engine is cold, the coolant does not flow to the radiator until the thermostat opens. This allows the engine to warm quickly.

Coolant Level Control

The engine cooling system contains an engine coolant level switch which alerts the driver in the event of a coolant loss. When the engine coolant level switch reads a low coolant level in the surge tank, the switch opens. This sends a coolant loss signal to the instrument panel cluster (IPC) by the coolant level switch signal circuit. Ground is provided for the coolant level control.

Cooling Cycle

Coolant flows from the radiator outlet and into the water pump inlet. Some coolant flows from the water pump, to the heater core, then back to the water pump. This provides the passenger compartment with heat and defrost capability as the coolant warms up.

Coolant also flows from the water pump outlet and into the engine block. In the engine block, the coolant circulates through the water jackets surrounding the cylinders where it absorbs heat.

The coolant then flows through the cylinder head gasket openings and into the cylinder heads. In the cylinder heads, the coolant flows through the water jackets surrounding the combustion chambers and valve seats, where it absorbs additional heat.

Some engine applications, coolant is also directed to the throttle body. There it circulates through passages in the casting. The coolant assists in regulating the throttle body temperature.

From the cylinder heads, the coolant flows to the thermostat. The flow of coolant will either be stopped at the thermostat until the engine reaches operating temperature or it will flow through the thermostat and into the radiator where it is cooled. At this point, the coolant flow cycle is completed.

Efficient operation of the cooling system requires proper functioning of all cooling system components. The cooling system consists of the following components

Coolant

The engine coolant is a solution made up of a 50-50 mixture of DEX-COOL and suitable drinking water. The coolant solution carries excess heat away from the engine to the radiator, where the heat is dissipated to the atmosphere.

Radiator

The radiator is a heat exchanger. It consists of a core and 2 tanks. The aluminum core is a tube and fin cross-flow design that extends from the inlet tank to the outlet tank. Fins are placed around the outside of the tubes to improve heat transfer to the atmosphere. The inlet and outlet tanks are a molded high temperature, nylon reinforced plastic material. A high temperature rubber gasket seals the tank flange edge to the aluminum core. The tanks are clamped to the core with clinch tabs. The tabs are part of the aluminum header at each end of the core. The radiator also has a drain cock located in the bottom of the left hand tank. The drain cock unit includes the drain cock and drain cock seal.

The radiator removes heat from the coolant passing through it. The fins on the core transfer heat from the coolant passing through the tubes. As air passes between the fins, it absorbs heat and cools the coolant.

During vehicle use, the coolant is heated and expands. The increased coolant volume flows into the surge tank. As the coolant circulates, any air is allowed to bubble out. Coolant without air bubbles absorbs heat much better than coolant with bubbles.

Coolant Recovery System

The coolant recovery system consists of a plastic coolant recovery reservoir, an overflow tube, and a pressure cap on the radiator. The recovery reservoir is also called a recovery tank or expansion tank. It is partially filled with coolant and is connected to the radiator fill neck with the overflow tube. Coolant can flow back and forth between the radiator and the reservoir.

In effect, a cooling system with a coolant recovery reservoir is a closed system. When the pressure in the cooling system gets too high, it will open the pressure valve in the pressure cap. This allows the coolant, which has expanded due to being heated, to flow through the overflow tube and into the recovery reservoir. As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum opens the vacuum valve in the pressure cap, allowing some of the coolant in the reservoir to be siphoned back into the radiator. Under normal operating conditions, no coolant is lost. Although the coolant level in the recovery reservoir goes up and down, the radiator and cooling system are kept full. An advantage to using a coolant recovery reservoir is that it eliminates almost all air bubbles from the cooling system. Coolant without air bubbles absorbs heat much better than coolant with bubbles.

Pressure Cap

The pressure cap seals the cooling system. It contains a blow off or pressure relief valve and a vacuum or atmospheric valve. The pressure valve is held against its seat by a spring, which protects the radiator from excessive cooling system pressure. The vacuum valve is held against its seat by a spring, which permits opening of the valve to relieve vacuum created in the cooling system as it cools off. The vacuum, if not relieved, might cause the radiator and/or coolant hoses to collapse.

The pressure cap allows cooling system pressure to build up as the temperature increases. As the pressure builds, the boiling point of the coolant increases. Engine coolant can be safely run at a temperature much higher than the boiling point of the coolant at atmospheric pressure. The hotter the coolant is, the faster the heat transfers from the radiator to the cooler, passing air.

The pressure in the cooling system can get too high. When the cooling system pressure exceeds the rating of the pressure cap, it raises the pressure valve, venting the excess pressure.

As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum causes the vacuum valve to open, allowing outside air into the surge tank. This equalizes the pressure in the cooling system with atmospheric pressure, preventing the radiator and coolant hoses from collapsing.

Cooling Fan and Clutch

The engine cooling fan and clutch are driven by the crankshaft via the drive belt. The cooling fan draws air through the radiator to improve the transfer of heat from the coolant to the atmosphere. As the fan blades spin, they pull cool, outside air past the radiator core. The fan clutch drives the cooling fan. The fan clutch controls the amount of torque that is transmitted from the crankshaft to the fan blades. The clutch allows more torque to engage on the fan when the engine operating temperature increases and/or the vehicle speed is low. As the torque increases, the fan turns more quickly. The fan clutch decreases the torque applied to the cooling fan when the engine temperature decreases and/or the vehicle speed is high. As the torque decreases, the fan speed decreases.

Air Baffles and Seals

The cooling system uses deflectors, air baffles and air seals to increase cooling system capability. Deflectors are installed under the vehicle to redirect airflow beneath the vehicle and through the radiator to increase engine cooling. Air baffles are also used to direct airflow through the radiator and increase cooling capability. Air seals prevent air from bypassing the radiator and A/C condenser, and prevent recirculation of hot air for better hot weather cooling and A/C condenser performance.

Water Pump

The water pump is a centrifugal vane impeller type pump. The pump consists of a housing with coolant inlet and outlet passages, a retaining plate, pulley and an impeller. The impeller is mounted on the pump shaft, and consists of a series of flat or curved blades or vanes on a flat plate. When the impeller rotates, the coolant between the vanes is thrown outward by centrifugal force. The impeller shaft is supported by one or more sealed bearings. The sealed bearings never need to be lubricated. Grease cannot leak out, dirt and water cannot get in as long as the seal is not damaged or worn.

The purpose of the water pump is to circulate coolant throughout the cooling system. The water pump is driven by the crankshaft via the drive belt.

Thermostat

The thermostat is a coolant flow control component. It's purpose is to help regulate the operating temperature of the engine. It utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a small piston. When the element is heated, it expands and exerts pressure against a small piston. This pressure forces the valve to open. As the element is cooled, it contracts. This contraction allows a spring to push the valve closed.

When the coolant temperature is below 85°C (185°F) for diesel engines and below 91°C (195°F) for gas engines, the thermostat valve remains closed. This prevents circulation of the coolant from the radiator and allows the engine to warm up. After the coolant temperature reaches 85°C (185°F) or 91°C (195°F), the thermostat valve will open. The coolant is then allowed to circulate through the thermostat to the engine and then to the radiator where the engine heat is dissipated to the atmosphere. The thermostat also provides a restriction in the cooling system, after it has opened. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block.

Engine Oil Cooler

The engine oil cooler is a heat exchanger. It is located inside the left side end tank of the radiator. The engine oil temperature is controlled by the temperature of the engine coolant that surrounds the oil cooler in the radiator.

The engine oil pump pumps the oil through the engine oil cooler line to the oil cooler. The oil then flows through the cooler where the engine coolant absorbs heat from the oil. The oil is then pumped through the oil cooler return line, to the oil filter, to the engine block oil system.

Transmission Oil Cooler

The transmission oil cooler is a heat exchanger. It is located inside the right side end tank of the radiator. The transmission fluid temperature is regulated by the temperature of the engine coolant in the radiator.

The transmission oil pump, pumps the fluid through the transmission oil cooler line to the transmission oil cooler. The fluid then flows through the cooler where the engine coolant absorbs heat from the fluid. The fluid is then pumped through the transmission oil cooler return line, to the transmission.

Illustration Tool Number/ Description J 24460-01 Cooling System Pressure Tester J 24731 Tempil Stick J 26568 Coolant and Battery Fluid Tester J 38185 Hose Clamp Pliers J 39529 Wiper Linkage Installer J 41240 Fan Clutch Remover and Installer J 42401 Radiator Cap and Surge Tank Test Adapter GE 47716 Vac-N-Fill Coolant Refill Tool

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See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• COMPONENT CONNECTOR END VIEWS - INDEX
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Temperature Versus Resistance
• Diagnostic Repair Verification
• Diagnostic Trouble Code (DTC) List - Vehicle
• Instrument Cluster Description and Operation
• Audible Warnings Description and Operation
• Coolant in Combustion Chamber
• Coolant in Engine Oil
• Approximate Fluid Capacities
• Heater Core Replacement
• Engine Oil and Oil Filter Replacement
• Engine Oil and Oil Filter Replacement
• Engine Oil and Oil Filter Replacement
• Engine Coolant/Water in Transmission
• Engine Coolant/Water in Transmission
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Coolant in Engine Oil
• Coolant in Combustion Chamber
• Coolant in Engine Oil
• Lower Engine Noise, Regardless of Engine Speed
• Lower Engine Noise, Regardless of Engine Speed
• Lower Engine Noise, Regardless of Engine Speed
• Cylinder Leakage Test
• Cylinder Leakage Test
• Cylinder Leakage Test
• Lifting and Jacking the Vehicle
• Fastener Caution
• Battery Negative Cable Disconnection and Connection
• Air Cleaner Assembly Replacement
• Grille Replacement (Base)
• Front Bumper Replacement
• Air Cleaner Assembly Replacement
• Engine Cover Replacement
• Exterior Trim Emblem Removal Caution
• Turbocharger Exhaust Pipe Replacement (LGH)
• Coolant Addition Caution
• Air Cleaner Resonator Outlet Duct Replacement
• Water Pump Cleaning and Inspection
• Crankshaft Balancer Replacement
• Adhesives, Fluids, Lubricants, and Sealers
• Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection (4L60-E/4L65-E/4L70-E)
• Tire and Wheel Removal and Installation (6-Lug Wheel)
• DTC P00B3 or P00B4
• Cooling System Draining and Filling (Vac N Fill)
• Engine Overheating
• Thermostat Diagnosis
• Fan Clutch Diagnosis
• Loss of Coolant
• Engine Fails To Reach Normal Operating Temperature
• Cooling System Leak Testing
• Pressure Cap Testing
• Fastener Tightening Specifications
• Flushing
• Adhesives, Fluids, Lubricants, and Sealers
• Radiator Inlet Hose Replacement (LGH)
• Radiator Outlet Hose Replacement (LGH)