Engine Cooling System Cadillac STS I

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Cooling System Connector End Views

After Boil Heater Pump Connector End (LH2/V92/V03) Connector Part Information OEM: 12131678 Service: 2-Way F Delphi (BK) Terminal Part Information Terminal: Terminal Seal: Release Tool: Core Crimp: Insulation Crimp: Test Probe: Pin Wire Color Circuit No. Function 1 BK/WH 1551 Signal Ground 2 PK 5126 After Boil Heater Pump Supply Voltage

Coolant Level Switch Connector End Connector Part Information OEM: 12052641 Service: 12102747 2-Way F Metri-Pack 150 Series (BK) Terminal Part Information Terminal: Terminal Seal: Release Tool: Core Crimp: Insulation Crimp: Test Probe: Pin Wire Color Circuit No. Function A L-GN 1478 Coolant Level Switch Signal B BK 150 Ground

Cooling Fan - Left Connector End (w/ V03/V09/V92) Connector Part Information OEM: 7283-5596-10 2-Way F YESC (DK-GY) Terminal Part Information Terminal: Terminal Seal: Release Tool: Core Crimp: Insulation Crimp: Test Probe: Pin Wire Color Circuit No. Function 1 GY 532 Cooling Fan Motor Supply Voltage (2) 2 WH 504 Cooling Fan Motor Low Reference

Cooling Fan - Left Connector End (w/o V03/V09/V92) Connector Part Information OEM: 7282-5596-10 2-Way M YESC 6.3WP (DK-GY) Terminal Part Information Terminal: Terminal Seal: Release Tool: Core Crimp: Insulation Crimp: Test Probe: Pin Wire Color Circuit No. Function 1 GY 532 Cooling Fan Motor Supply Voltage (2) 2 WH 504 Cooling Fan Motor Low Reference

Cooling Fan - Right Connector End Connector Part Information OEM: 7283-5596-10 2-Way F YESC (DK-GY) Terminal Part Information Terminal: Terminal Seal: Release Tool: Core Crimp: Insulation Crimp: Test Probe: Pin Wire Color Circuit No. Function 1 L-BU 409 Cooling Fan Motor Supply Voltage (1) 2 BK 250 Ground

Diagnostic Starting Point - Engine Cooling

Begin the system diagnosis with the Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check will provide the following information

1. The identification of the control modules which command the system.
2. The ability of the control modules to communicate through the serial data circuit.
3. The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

Scan Tool Output Controls

Engine Control Module (ECM) Scan Tool Output Controls

HVAC Control Module Scan Tool Output Controls

Scan Tool Data List

Scan Tool Data List

Circuit Description

The engine control module (ECM) controls the low speed cooling fan operation by grounding the low speed fan relay control circuit with an internal solid state device called a driver. For high speed cooling fan operation, the ECM grounds the high speed and S/P relay control circuit at the same time the low speed control circuit is grounded. Battery positive voltage is supplied to the low speed, high speed and S/P fan relays. When the ECM is commanding a fan relay ON, the voltage of the control circuit should be low, near 0 volts. When the ECM is commanding a fan relay OFF, the voltage potential of the control circuit should be high, near battery voltage.

The ECM monitors the relay control circuits for the following conditions

1. Short to ground
2. Short to voltage
3. An open circuit

If the ECM detects an improper voltage level on the low or high speed driver circuits, then code P0480, P0481, P0691, P0692, P0693, or P0694, will set and the effected driver will be disabled.

1. Cooling fan relay 1 control circuit refers to the low speed cooling fan relay
2. Cooling fan relay 2 control circuit refers to the high speed cooling fan relay

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P0480 Cooling Fan Relay 1 Control Circuit
2. DTC P0481 Cooling Fan Relay 2 Control Circuit
3. DTC P0691 Cooling Fan Relay 1 Control Circuit Low Voltage
4. DTC P0692 Cooling Fan Relay 1 Control Circuit High Voltage
5. DTC P0693 Cooling Fan Relay 2 Control Circuit Low Voltage
6. DTC P0694 Cooling Fan Relay 2 Control Circuit High Voltage

Conditions for Running the DTC

1. The ignition voltage is between 8-18 volts.
2. The engine speed is more than 40 RPM.
3. The ECM driver transitions from ON to OFF or from OFF to ON.

Conditions for Setting the DTC

1. P0481-The ECM detects an open circuit on the high speed cooling fan relay control circuit.
2. P0693 -The ECM detects a short to ground on the high speed cooling fan relay control circuit.
3. P0694 -The ECM detects a short to voltage on the high speed cooling fan relay control circuit.
4. P0480 -The ECM detects an open on the low speed cooling fan relay control circuit.
5. P0691 -The ECM detects a short to ground on the low speed cooling fan relay control circuit.
6. P0692 -The ECM detects a short to voltage on the low speed cooling fan relay control circuit.
7. The above condition is present for one second.

Action Taken When the DTC Sets

1. The ECM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
2. The ECM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

Conditions for Clearing the MIL/DTC

1. The ECM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
2. The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. Use the scan tool Clear DTC Information function.

Diagnostic Aids

1. If the condition is not present, refer to «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2004-2007/remont/body-electrical/#wiring-systems-electrical-power-management-introduction__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. Review the Freeze/Failure Records vehicle mileage since the diagnostic test failed. This may help determine how often the condition that caused the DTC to be set occurs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 2: Listen for an audible click when the low speed fan relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3: Listen for an audible click when the S/P and high speed fan relays operate. Command both the ON and OFF states. Repeat the commands as necessary.

DTC P0480, P0481, P0691, P0692, P0693, or P0694

The engine control module (ECM) uses the engine coolant temperature (ECT) sensor to monitor the engine for an over temperature condition. This condition occurs when the coolant temperature is above 131°C (268°F). When an over temperature condition is present, DTC P1258 will set. The ECM will disable 2 groups of 4 cylinders by turning OFF the fuel injectors. By switching between the 2 groups of cylinders, the ECM is able to reduce the temperature of the coolant.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P1258 Engine Coolant Overtemperature-Protection Mode Active

The ignition is ON.

1. The ECM detects an ECT over 131°C (268°F).
2. The above condition is present for at least 3 seconds.

1. The ECM will illuminate the malfunction indicator lamp (MIL) during the first trip in which the diagnostic test has been run and failed.
2. The ECM will signal the instrument panel cluster (IPC) to turn ON the Service Engine Soon indicator.
3. The ECM will alternately disable 2 groups of 4 cylinders by turning OFF the fuel injectors.
4. The ECM will store conditions which were present when the DTC set in Freeze Frame Data.
5. The ECM will command the fan on high speed.

1. The ECM will turn the MIL OFF after 3 consecutive trips that the diagnostic has been run and passed.
2. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. The DTC can be cleared by using the scan tool Clear DTC Information function.

DTC P1258

Symptoms - Engine Cooling

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Cooling System. Refer to «Checking Aftermarket Accessories»(/cadillac/sts/i-2004-2007/remont/body-electrical/#wiring-systems-electrical-power-management-introduction__checking-aftermarket-accessories) in Wiring Systems.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Inspect the surge tank reservoir for the proper coolant level.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

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

1. «Low Engine Coolant Indicator Always On»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__low-engine-coolant-indicator-always-on)
2. «Cooling Fan Always On»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-always-on)
3. «Cooling Fan Inoperative»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-inoperative)
4. «Engine Overheating»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system)
5. «Loss of Coolant»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant)
6. «Thermostat Diagnosis»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system)
7. «Engine Fails To Reach Normal Operating Temperature»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system)
8. «Pressure Cap Testing»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__pressure-cap-testing)
9. «Cooling System Leak Testing»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing)

Low Engine Coolant Indicator Always On

Low Engine Coolant Indicator Always On

Cooling Fan Always On

Cooling Fan Always On

Cooling Fan Inoperative

Cooling Fan Inoperative

After Boil Coolant Pump Inoperative

After Boil Coolant Pump Inoperative

The engine may overheat due to an intermittent operation of one of the following components

1. The after boil heater pump
2. The coolant bypass solenoid
3. The coolant bypass valve
4. The mechanical cooling fan
5. The electric cooling fans
6. The thermostat

For electrical inspection of the cooling fans and the after boil heater pump, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Engine Overheating

Loss of Coolant

Loss of Coolant

Tools Required

J 24731 Tempilstick. See Special Tools .

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 operating range, by rubbing 87°C (188°F) and 97°C (206°F) sticks on the outlet coolant pipe, located between the thermostat housing and the inlet radiator hose.

1. Use a tempilstick in order to find the opening and the closing temperatures of the coolant thermostat. J 24731-188 tempilstick melts at 87°C (188°F). The thermostat should begin to open at 90°C (194°F). J 24731-206 tempilstick melts at 97°C (206°F). The thermostat should be fully open at 107°C (225°F).
2. Replace the coolant thermostat if it does not operate properly between this temperature range.

Coolant Heater Inoperative

Coolant Heater Inoperative

The engine may fail to reach normal operating temperature due to an intermittent operation of one of the following components

1. The thermostat
2. The electric fan system
3. The mechanical fan system

For electrical inspection of the electrical fan system, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

For mechanical fan system inspection, refer to Fan Clutch Diagnosis .

Engine Fails To Reach Normal Operating Temperature

Pressure Cap Testing

Tools Required

1. J 24460-01 Cooling System Pressure Tester. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
2. J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the J 24460-01 (1) with J 42401 (2) in order to test the pressure cap. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
4. Test the pressure cap for the following conditions: Pressure release when the J 24460-01 exceeds the pressure rating of the pressure cap. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Maintain the rated pressure for at least 10 seconds Note the rate of pressure loss.
5. Replace the pressure cap under the following conditions: The pressure cap does not release pressure which exceeds the rated pressure of the cap. The pressure cap does not hold the rated pressure.

Cooling System Leak Testing

Tools Required

1. J 24460-01 Cooling System Pressure Tester. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
2. J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__pressure-cap-testing) .
3. Wash the pressure cap mating surface with water.
4. Use the J 24460-01 (1) with J 42401 (2) in order to apply pressure to the cooling system. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Do not exceed the pressure cap rating.
5. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gage for any pressure loss.
6. Repair any leaks as required.

Fan Clutch Diagnosis

Fan Clutch Diagnosis

J 26568 Coolant and Battery Fluid Tester. See Special Tools .

Draining Procedure

1. Park the vehicle on a level surface.
2. Remove the surge tank cap.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) .
4. Remove the air deflector. Refer to «Air Deflector Replacement - Front»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-front-end) .
5. Place a drain pan under the radiator.
6. Insert a piece of clean flexible hose through the access hole in the cradle onto the radiator mounting pin.
7. Slowly loosen the drain cock and drain the coolant into the drain pan. Do not completely remove the drain cock.
8. Inspect the engine coolant for the following conditions: Discolored appearance - Follow the flush procedure. Refer to «Flushing»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__flushing) . Normal in appearance - Follow the Fill Procedure below.

Fill Procedure

1. Close the radiator drain cock.
2. Install the air deflector. Refer to «Air Deflector Replacement - Front»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-front-end) .
3. Lower the vehicle.
4. Slowly add a mixture of 50/50 DEX-COOL antifreeze and clean drinkable water to the cooling system through the top of the surge tank opening. Refer to «Capacities - Approximate Fluid»(/cadillac/sts/i-2004-2007/remont/lubrication-system/#maintenance-and-lubrication__capacities-approximate-fluid) .
5. Slowly fill the cooling system until the coolant stabilizes at 25 mm (1 inch) above the FULL COLD mark on the surge tank.
6. Install the surge tank cap.
7. Start the engine.
8. Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature.
9. Allow the engine to idle for 3 minutes.
10. Shut the engine OFF.
11. Allow the engine to cool.
12. Add or remove coolant as necessary from the surge tank until the level is stabilized at the FULL COLD mark.
13. Inspect the cooling system for leaks.
14. Using J 26568 inspect the concentration of the engine coolant. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .

Flushing

1. Block the drive wheels.
2. Place the transmission in PARK (P).
3. Engage the park brake.
4. Run the engine until the thermostat opens.
5. Stop the engine.
6. Follow the drain and fill procedure using only clean drinkable water. Repeat the procedure if necessary, until the fluid is nearly colorless. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Fill the cooling system when flushing is complete. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

Radiator Cleaning

Note. The radiator fins are necessary for good heat transfer. Do not brush the fins. This may cause damage to the fins, reducing heat transfer.

1. Some conditions may require the use of warm water and a mild detergent.
2. Clean the A/C condenser fins.
3. Clean between the A/C condenser and radiator.
4. Clean the radiator cooling fins.
5. Straighten any damaged cooling fins.

J 38185 Hose Clamp Pliers

Removal Procedure

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Disconnect the master cylinder fluid level sensor electrical connector and reposition aside.
3. Using the J 38185 , disengage and reposition the surge tank outlet hose clamp.
4. Disconnect the surge tank outlet hose.
5. Using the J 38185 , disengage and reposition the surge tank inlet hose clamp.
6. Disconnect the surge tank inlet hose.
7. Remove the surge tank bolt.
8. Remove the surge tank nut.
9. Disconnect the low coolant sensor electrical connector.
10. Remove the surge tank.

Installation Procedure

1. Install the surge tank.
2. Connect the low coolant sensor electrical connector.
3. Install the surge tank nut. Tighten: Tighten the nut to 9 N.m (80 lb in).
4. Install the surge tank bolt. Tighten: Tighten the bolt to 9 N.m (80 lb in).
5. Connect the surge tank inlet hose to the surge tank.
6. Using the J 38185 , resposition the hose clamp to secure the surge tank inlet hose.
7. Connect the surge tank outlet hose.
8. Using the J 38185 , resposition the hose clamp to secure the surge tank outlet hose.
9. Connect the master cylinder fluid level sensor electrical connector.
10. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using J 38185 , disengage the hose clamp at the surge tank (1) and disconnect the surge tank inlet hose (2).
3. Using J 38185 , disengage the hose clamp at the radiator and disconnect the surge tank inlet hose.
4. Using J 38185 , disengage the hose clamp at the throttle body assembly and disconnect the surge tank inlet hose.
5. Remove the surge tank inlet hose from the vehicle.

1. Using J 38185 , engage the hose clamp at the throttle body assembly and connect the surge tank inlet hose.
2. Using J 38185 , engage the hose clamp at the radiator and connect the surge tank inlet hose.
3. Position the surge tank inlet hose to the retaining feature of the air cleaner assembly.
4. Using J 38185 , engage the hose clamp at the surge tank (1) and connect the surge tank inlet hose (2).
5. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using J 38185 , disengage the clamp at the surge tank and disconnect the surge tank inlet hose.
3. Using J 38185 , disengage the clamp at the radiator and disconnect the surge tank inlet hose
4. Remove the surge tank inlet hose from the retaining features on the fan shroud and the air cleaner assembly.
5. Using J 38185 , disengage the clamp at the water housing assembly and disconnect the surge tank inlet hose
6. Remove the surge tank inlet hose from the vehicle.

1. Install the surge tank inlet hose.
2. Using J 38185 , install the surge tank inlet hose to the water housing assembly.
3. Insert the surge tank inlet hose into the retaining features on the fan shroud and the air cleaner housing assembly.
4. Using J 38185 , install the surge tank inlet hose to the radiator.
5. Using J 38185 , install the surge tank inlet hose to the surge tank.
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Position J 38185 to the clamp in order to remove the outlet hose (2) from the surge tank (1).
3. Loosen the bolt on the bracket which secures the surge tank outlet hose to the engine.
4. Position J 38185 to the clamp in order to remove the surge tank outlet hose from the thermostat assembly.
5. Remove the surge tank outlet hose/pipe from the engine.

1. Position the surge tank outlet hose/pipe to the engine.
2. Position J 38185 to the clamp in order to connect the surge tank outlet hose to the thermostat assembly.
3. Install the bolt to the bracket securing the surge tank outlet pipe to the engine. Tighten: Tighten the bolt to 9 N.m (80 lb in).
4. Position J 38185 to the clamp in order to connect the outlet hose (2) to the surge tank (1).
5. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L.
3. Compress the clamp (1) and remove the surge tank outlet hose from the surge tank (2).
4. Separate the hose (2) from the retaining features (1 and 3) on the front of dash.
5. Compress the clamp (2) and remove the surge tank outlet hose from the heater hose (1).
6. Remove the surge tank outlet hose/pipe from the engine compartment.

1. Position the surge tank outlet hose/pipe to the engine compartment.
2. Compress the clamp (2) and connect the surge tank outlet hose to the heater hose (1).
3. Install the hose (2) to the retaining features (1 and 3) on the front of dash.
4. Compress the clamp (1) and connect the surge tank outlet hose to the surge tank (2).
5. Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L.
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator inlet hose from the thermostat housing.
3. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator inlet hose from the radiator.
4. Remove the radiator inlet hose from the vehicle.

1. Install the inlet radiator hose into the vehicle.
2. Using the J 38185 , disengage the tension on the hose clamp and Install the radiator inlet hose to the radiator.
3. Using the J 38185 slide the clamp into the original position.
4. Using the J 38185 , disengage the tension on the hose clamp and install the radiator inlet hose to the thermostat housing.
5. Using the J 38185 slide the clamp into the original position.
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator inlet hose from the throttle body housing.
3. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator inlet hose from the radiator.
4. Remove the radiator inlet hose from the vehicle.

1. Install the inlet radiator hose into the vehicle.
2. Using the J 38185 , disengage the tension on the hose clamp and Install the radiator inlet hose to the radiator.
3. Using the J 38185 slide the clamp into the original position.
4. Using the J 38185 , disengage the tension on the hose clamp and install the radiator inlet hose to the throttle body housing.
5. Using the J 38185 slide the clamp into the original position.
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.
3. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator outlet hose from the thermostat housing.
4. Disconnect the radiator outlet hose from the support bracket.
5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
6. Remove the front air deflector retainers.
7. Remove the front air deflector.
8. Remove the engine control module (ECM) mounting nuts and reposition ECM aside.
9. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator outlet hose from the radiator.
10. Lower the vehicle.
11. Remove the radiator outlet hose from the vehicle.

1. Install the radiator outlet hose to the vehicle.
2. Raise the vehicle.
3. Using the J 38185 , disengage the tension on the hose clamp and install the radiator outlet hose to the radiator.
4. Using the J 38185 slide the clamp into the original position.
5. Position ECM on the mounting bracket.
6. Install the ECM to mounting nuts. Tighten: Tighten the nuts to 8 N.m (71 lb in).
7. Install the front air deflector.
8. Install the front air deflector retainers.
9. Lower the vehicle.
10. Using the J 38185 , disengage the tension on the hose clamp and install the radiator outlet hose to the thermostat housing.
11. Using the J 38185 slide the clamp into the original position.
12. Install the radiator outlet hose to the support bracket.
13. Install the air intake duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.
14. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.
3. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator outlet hose from the thermostat housing.
4. Disconnect the radiator outlet hose from the support bracket.
5. Using the J 38185 , disengage the tension on the radiator outlet hose (1) clamp.
6. Disconnect the radiator outlet hose (1) from the afterboil coolant pump.
7. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
8. Remove the front air deflector retainers.
9. Remove the front air deflector.
10. Remove the engine control module (ECM) mounting nuts and reposition ECM aside.
11. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator outlet hose from the radiator.
12. Lower the vehicle.
13. Remove the radiator outlet hose from the vehicle.

1. Install the radiator outlet hose to the vehicle.
2. Raise the vehicle.
3. Using the J 38185 , disengage the tension on the hose clamp and install the radiator outlet hose to the radiator.
4. Using the J 38185 slide the clamp into the original position.
5. Position ECM on the mounting bracket.
6. Install the ECM to mounting nuts. Tighten: Tighten the nuts to 8 N.m (71 lb in).
7. Install the front air deflector.
8. Install the front air deflector retainers.
9. Lower the vehicle.
10. Connect the radiator outlet hose (1) to the afterboil coolant pump.
11. Using the J 38185 , reposition the radiator outlet hose (1) clamp to secure the radiator outlet hose to the afterboil coolant pump.
12. Using the J 38185 , disengage the tension on the hose clamp and install the radiator outlet hose to the thermostat housing.
13. Using the J 38185 slide the clamp into the original position.
14. Install the radiator outlet hose to the support bracket.
15. Install the air intake duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.
16. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the radiator inlet hose. Refer to «Radiator Hose Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator outlet hose from the thermostat housing.
4. Disconnect the radiator outlet hose from the engine support bracket.
5. Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) in Engine Control - 3.6L.
6. Using the J 38185 , disengage the tension on the hose clamp and remove the radiator outlet hose from the radiator.
7. Remove the radiator outlet hose from the vehicle.

1. Install the radiator outlet hose to the vehicle.
2. Using the J 38185 , disengage the tension on the hose clamp and install the radiator outlet hose to the radiator.
3. Using the J 38185 slide the clamp into the original position.
4. Using the J 38185 , disengage the tension on the hose clamp and install the radiator outlet hose to the thermostat housing.
5. Using the J 38185 slide the clamp into the original position.
6. Install the radiator outlet hose to the engine support bracket.
7. Install the radiator inlet hose. Refer to «Radiator Hose Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 41240 Fan Clutch Remove and Installer. See Special Tools .

1. Remove the air cleaner intake duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.
2. Loosen the fan nut from the crank adapter shaft using J 41240 . See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) .
4. Disconnect the engine wiring harness from the engine frame and reposition aside.
5. Continue to loosen the fan nut and disconnect the fan from the crank adapter shaft.
6. Remove the fan from the vehicle.

1. Install the fan to the vehicle.
2. Connect the fan to the crank adapter shaft.
3. Connect the engine wiring harness to the engine frame.
4. Lower the vehicle.
5. Tighten the fan nut to the crank adapter shaft using J 41240 . See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Tighten: Tighten the nut to 100 N.m (74 lb ft).
6. Install the air cleaner intake duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.

J 41240 Fan Clutch Wrench. See Special Tools .

1. Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) in Engine Controls - 3.6L.
2. Loosen the fan nut from the crank adapter shaft using J 41240 . See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
3. Remove the fan from the vehicle.

1. Install the fan to the vehicle.
2. Tighten the fan nut to the crank adapter shaft using J 41240 . See «Special Tools»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Tighten: Tighten the nut to 100 N.m (74 lb ft).
3. Install the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) in Engine Controls - 3.6L.

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.
2. Disengage the surge tank inlet hose from the retaining features on the cooling fan shroud and reposition aside.
3. Remove the upper retaining bolts that secure the cooling fan shroud to the radiator.
4. Remove the LH lower retaining bolt that secures the cooling fan shroud to the radiator.
5. Disconnect the cooling fan electrical connectors.
6. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) .
7. Remove the front air deflector retainers.
8. Remove the front air deflector.
9. Remove the RH lower retaining bolt that secures the cooling fan shroud to the radiator.
10. Disconnect and reposition the engine wiring harness from the engine frame and reposition.
11. Remove the retaining bolts that secure the power steering line to the cooling fan shroud.
12. Remove the retaining bolts that secure the transmission oil cooler lines to the cooling fan shroud.
13. Lower the vehicle.
14. Remove the cooling fan assembly.

1. Install the cooling fan assembly.
2. Raise the vehicle.
3. Install the retaining bolts that secure the transmission oil cooler lines to the cooling fan shroud. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
4. Install the retaining bolts that secure the power steering lines to the cooling fan shroud. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
5. Connect the engine wiring harness to the engine frame.
6. Install the RH lower retaining bolt that secures the cooling fan shroud to the radiator. Tighten: Tighten the bolt to 5.4 N.m (48 lb in).
7. Install the front air deflector.
8. Install the front air deflector retainers.
9. Lower the vehicle.
10. Connect the cooling fan electrical connectors.
11. Install the upper retaining bolts that secure the cooling fan shroud to the radiator. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
12. Install the left side lower retaining bolt that secures the cooling fan shroud to the radiator. Tighten: Tighten the bolt to 5.4 N.m (48 lb in).
13. Engage the surge tank inlet hose to the retaining features on the cooling fan shroud.
14. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.

1. Remove the upper mounting bolts that secure the auxiliary cooling fan assembly to the condenser.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) .
3. Remove the front air deflector retainers.
4. Remove the front air deflector.
5. Disconnect the electrical connectors from the auxiliary cooling fan assembly.
6. Remove the lower mounting bolts that secure the auxiliary cooling fan assembly to the condenser.
7. Remove the auxiliary cooling fan assembly.

1. Install the auxiliary cooling fan assembly.
2. Install the mounting bolts that secure the auxiliary cooling fan assembly to the condenser. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
3. Connect the electrical connectors to the auxiliary cooling fan assembly.
4. Install the front air deflector.
5. Install the front air deflector retainers.
6. Lower the vehicle.
7. Install the upper mounting bolts that secure the auxiliary cooling fan assembly to the condenser. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) in Engine Controls - 3.6L.
2. Disconnect the cooling fan electrical connectors.
3. Disconnect the condenser tube from the cooling fan shroud retainer clip.
4. Disengage the surge tank inlet hose from the retaining features on the cooling fan shroud and reposition aside.
5. Remove the retaining bolts that secure the cooling fan shroud to the radiator.
6. Remove the cooling fan assembly.

1. Install the cooling fan assembly.
2. Install the retaining bolts that secure the cooling fan shroud to the radiator. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
3. Engage the surge tank inlet hose to the retaining features on the cooling fan shroud.
4. Connect the condenser tube to the cooling fan shroud retainer clip.
5. Connect the cooling fan electrical connectors.
6. Install the air cleaner outlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) in Engine Controls - 3.6L.

1. Remove the cooling fan assembly. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the fan blade retaining nut (1) from the motor.
3. Remove the fan blade from the motor shaft.
4. Remove the motor retaining screws (1).
5. Remove the motor from the shroud.

1. Install the motor to the shroud.
2. Install the cooling fan motor retaining screws (1). Tighten: Tighten the screws to 5 N.m (44 lb in).
3. Install the fan blade to the motor shaft.
4. Rotate the fan until the fan drops onto the shaft.
5. Install the fan blade retaining nut (1) to the motor. Tighten: Tighten the nut to 7 N.m (62 lb in).
6. Install the cooling fan assembly. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the engine cooling fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. With the aid of an assistant, tap the engine ignition until the fan bracket to crankshaft balancer bolts are accessible.
3. Remove the fan bracket to crankshaft balancer bolts.
4. Remove the fan bracket to engine block bolts.
5. Remove the fan bracket from the vehicle.

1. Install the fan bracket to the engine.
2. Install but DO NOT tighten the fan bracket to engine block bolts.
3. If necessary, with the aid of an assistant, tap the engine ignition until the fan bracket to crankshaft balancer bolt holes are accessible.
4. Install the fan bracket to crankshaft balancer bolts. Tighten: Tighten the fan bracket to crankshaft balancer bolts to 24 N.m (18 lb ft). Tighten the fan bracket to engine block bolts to 24 N.m (18 lb ft).
5. Install the engine cooling fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the engine cooling fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the fan bracket to engine block bolts.
3. Remove the fan bracket from the vehicle.
4. Remove the adapter studs from the crankshaft balancer, if necessary.

1. If previously removed, install the adapter studs to the crankshaft balancer. Tighten: Tighten the engine cooling fan adapter studs to 22 N.m (16 lb ft).
2. Align the adapter assembly to the studs on the crankshaft.
3. Install the fan adapter to the engine.
4. Install the fan adapter to engine block bolts. Tighten: Tighten the fan adapter to engine block bolts to 50 N.m (37 lb ft).
5. Install the engine cooling fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls-4.6L (LH2).
3. Remove the radiator hose from the thermostat housing. Refer to «Radiator Hose Replacement - Outlet (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the heater hose from the thermostat housing. Refer to «Heater Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Outlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
5. Remove the thermostat housing bolts.
6. Remove the thermostat housing (1) with thermostat (3), from the water housing.
7. Remove and discard the seal ring (2).
8. Remove the thermostat from the thermostat housing.

1. Clean the thermostat housing and water housing sealing surfaces.
2. Install the thermostat to the thermostat housing.
3. Install the NEW seal (2) to the thermostat housing.
4. Install the thermostat housing (1) with the thermostat (3) and the seal (2) to the water housing.
5. Install the thermostat housing bolts. Tighten: Tighten the thermostat housing bolts to 10 N.m (89 lb in).
6. Install the heater hose to the thermostat housing. Refer to «Heater Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Outlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
7. Install the radiator hose to the thermostat housing. Refer to «Radiator Hose Replacement - Outlet (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls-4.6L (LH2).
9. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Disconnect the heater hoses from the heater core. Refer to «Heater Hose Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Inlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) and «Heater Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Outlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
2. Remove the thermostat. Refer to «Thermostat Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Thermostat Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the thermostat housing bolts.
4. Remove the thermostat housing with the heater pipes, hoses and bolts.
5. Carefully clean the sealing surfaces with a plastic gasket scraper such as J 28410 or equivalent.

1. Assemble the heater pipes and hoses to the thermostat housing.
2. Install a new gasket to the thermostat housing.
3. Install the thermostat housing bolts to the thermostat housing. Partially install the thermostat housing bolts in order to retain the gasket.
4. Install the thermostat housing with the heater pipes, heater hoses, gasket and bolts.
5. Install the thermostat housing bolts. Tighten: Tighten the thermostat housing bolts to 20 N.m (15 lb ft).
6. Install the thermostat. Refer to «Thermostat Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Thermostat Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Connect the heater hoses to the heater core. Refer to «Heater Hose Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Inlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) and «Heater Hose Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Inlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
3. Remove the radiator hose from the thermostat housing. Refer to «Radiator Hose Replacement - Outlet (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the heater hose from the thermostat housing. Refer to «Heater Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Outlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
5. Remove the thermostat housing bolts.
6. Remove the thermostat housing (1) with thermostat (3), from the water housing.
7. Remove and discard the seal ring (2).
8. Remove the thermostat from the thermostat housing.

1. Clean the thermostat housing and water housing sealing surfaces.
2. Install the new thermostat to the thermostat housing.
3. Install the NEW seal (2) to the thermostat housing.
4. Install the thermostat housing (1) with the thermostat (3) and the seal (2) to the water housing.
5. Install the thermostat housing bolts. Tighten: Tighten the thermostat housing bolts to 10 N.m (89 lb in).
6. Install the heater hose to the thermostat housing. Refer to «Heater Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Heater Hose Replacement - Outlet (LH2)»(/cadillac/sts/i-2004-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
7. Install the radiator hose to the thermostat housing. Refer to «Radiator Hose Replacement - Outlet (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
9. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the upper intake manifold with the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-36l-ly7-2-of-6) in Engine Mechanical - 3.6L (LY7).
3. Disconnect the surge tank hose from the thermostat.
4. Remove the coolant pipe/thermostat housing bolt (2).
5. Remove the coolant pipe upper bolt (7).
6. Remove the coolant inlet pipe (4) from the thermostat.
7. Remove the thermostat bolts.
8. Remove the thermostat and discard the thermostat seal.

1. Install the thermostat with a NEW thermostat seal.
2. Install the thermostat bolts. Tighten: Tighten the thermostat bolts to 10 N.m (89 lb in).
3. Install the coolant pipe (4), NEW seal, and fasteners (2 and 7). Refer to «Coolant Pipe Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Install the surge tank hose to the thermostat.
5. Install the upper intake manifold with the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-36l-ly7-2-of-6) in Engine Mechanical - 3.6L (LY7).
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the throttle body. Refer to «Throttle Body Assembly Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
3. Remove the manifold absolute pressure (MAP) sensor (3). Refer to «Manifold Absolute Pressure (MAP) Sensor Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
4. Disconnect the evaporative emission (EVAP) canister purge solenoid valve hose and electrical connector. Refer to «Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
5. Compress the clamps and remove the following hoses from the thermostat and the water housing: The heater inlet hose (1) The radiator inlet hose (2) The heater outlet hose (3) The bypass hose (4) The surge tank inlet hose
6. Loosen the intake manifold duct clamp (1).
7. Remove the bolts (1, 2) securing the water outlet housing to the cylinder heads.
8. Remove the water outlet housing from the vehicle.
9. Discard the water outlet housing gaskets.
10. Clean and inspect the water outlet housing. Refer to «Water Outlet Housing Cleaning and Inspection»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-5-of-6) in Engine Mechanical - 4.6L.
11. Remove the following components from the water outlet housing if replacement is necessary: The intake manifold inlet duct and clamp The surge tank inlet hose fitting The heater inlet hose fitting The evaporative emission (EVAP) canister purge solenoid valve - Refer to «Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L.

1. Install the following components to the water outlet housing if previously removed: The intake manifold inlet duct and clamp Tighten: Tighten the manifold inlet duct clamp to 6 N.m (53 lb in). The surge tank inlet hose fitting Tighten: Tighten the surge tank inlet hose fitting to 18 N.m (13 lb ft). The heater inlet hose fitting Tighten: Tighten the heater inlet hose fitting to 20 N.m (15 lb ft). The (EVAP) canister purge solenoid valve Tighten: Tighten the purge solenoid valve bolt to 12 N.m (106 lb in).
2. Install NEW water outlet housing gaskets.
3. Bolt (2) is approximately 10 mm longer than the other three bolts (1).
4. Install the water outlet housing to the vehicle.
5. Install the water outlet housing bolts. Tighten: Tighten the water outlet housing bolts to 25 N.m (18 lb ft).
6. Tighten the intake manifold duct clamp (1). Tighten: Tighten the intake manifold inlet duct clamp to 6 N.m (53 lb in).
7. Compress the clamps and install the following hoses to the thermostat and the water housing: The heater inlet hose (1) The radiator inlet hose (2) The heater outlet hose (3) The bypass hose (4) The surge tank inlet hose
8. Connect the evaporative emission (EVAP) canister purge solenoid valve hose and electrical connector. Refer to «Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
9. Install the manifold absolute pressure (MAP) sensor (3). Refer to «Manifold Absolute Pressure (MAP) Sensor Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
10. Install the throttle body. Refer to «Throttle Body Assembly Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
11. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the radiator hose from the water outlet. Refer to «Radiator Hose Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the water outlet housing bolts.
4. Remove the water outlet.
5. Remove and discard the water outlet seals.
6. Clean the water outlet housing sealing surfaces.

1. Install NEW water outlet housing seals.
2. Install the water outlet.
3. Install the water outlet bolts. Tighten: Tighten the water outlet housing bolts to 10 N.m (89 lb in).
4. Install the radiator hose to the water outlet. Refer to «Radiator Hose Replacement - Inlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
2. Remove the coolant pipe to generator bracket bolt.
3. Lower the vehicle.
4. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Disconnect the radiator outlet hose from the coolant pipe. Refer to «Radiator Hose Replacement - Outlet (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Remove the wiring harnesses from the coolant inlet pipe.
7. Remove the coolant pipe to thermostat bolt.
8. Remove the coolant pipe to cylinder head bolt.
9. Remove the coolant pipe.

1. Install the coolant pipe.
2. Loose assemble all the coolant pipe bolts.
3. Install the coolant pipe to thermostat bolt. Tighten: Tighten the coolant pipe to thermostat bolt to 23 N.m (17 lb ft).
4. Install the coolant pipe to cylinder head bolt. Tighten: Tighten the coolant pipe to cylinder head bolt to 50 N.m (37 lb ft).
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
6. Install the coolant pipe to generator bracket bolt. Tighten: Tighten the coolant pipe to generator bracket bolt to 23 N.m (17 lb ft).
7. Connect the radiator outlet hose to the coolant pipe. Refer to «Radiator Hose Replacement - Outlet (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the wiring harnesses to the coolant inlet pipe.
9. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
3. Compress the clamp, and remove the heater outlet hose (3) from the thermostat housing in order to gain access to the bypass hose.
4. Compress the clamps (1, 3) and remove the bypass hose (2) from the water outlet housing and the front cover.

1. Compress the clamps (1, 3) and install the bypass hose (2) to the water outlet housing and the front cover.
2. Compress the clamp, and install the heater outlet hose (3) to the thermostat housing.
3. Compress the clamp, and remove the heater outlet hose (3) from the thermostat housing in order to gain access to the bypass hose.
4. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in Engine Controls - 4.6L (LH2).
5. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the cooling fan. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the water pump drive belt. Refer to «Drive Belt Replacement - Air Conditioning, Power Steering and Water Pump»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
4. Remove the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement - Air Conditioning, Power Steering and Water Pump»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
5. Remove the water pump pulley bolts.
6. Remove the water pump pulley from the water pump.
7. Remove the water pump bolts.
8. Remove the water pump and seal. Do not reuse the seal.
9. Clean the water pump mating surfaces.
10. Clean and inspect the water pump. Refer to «Water Pump Cleaning and Inspection»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-5-of-6__water-pump-cleaning-and-inspection) in Engine Mechanical - 4.6L (LH2).

1. Install the water pump and NEW seal to the engine front cover.
2. Install the water pump bolts. Tighten: Tighten the water pump bolts to 10 N.m (89 lb in).
3. Install the water pump pulley to the water pump.
4. Install the water pump pulley bolts. Tighten: Tighten the water pump pulley bolts to 12 N.m (106 lb in).
5. Install the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement - Air Conditioning, Power Steering and Water Pump»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
6. Install the water pump drive belt. Refer to «Drive Belt Replacement - Air Conditioning, Power Steering and Water Pump»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
7. Install the cooling fan. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

EN 46104 Water Pump Pulley Holding Tool

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the generator drive belt. Refer to «Drive Belt Replacement - Generator and Water Pump»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-36l-ly7-2-of-6) in Engine Mechanical - 3.6L (LY7).
3. Use the EN 46104 (1) in order to retain the water pump pulley.
4. Remove the water pump pulley bolts.
5. Remove the water pump pulley.
6. Remove the water pump bolts.
7. Remove the water pump.
8. Remove and DISCARD the water pump seal.
9. Carefully clean the water pump sealing surfaces.

1. Install a NEW water pump seal.
2. Install the water pump.
3. Install the water pump bolts. Tighten: Tighten the water pump bolts to 10 N.m (89 lb in).
4. Install the water pump pulley and the water pump pulley bolts.
5. Use the EN 46104 (1) in order to retain the water pump pulley.
6. Install the water pump pulley bolts. Tighten: Tighten the water pump pulley bolts to 12 N.m (106 lb in).
7. Install the generator drive belt. Refer to «Drive Belt Replacement - Generator and Water Pump»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-36l-ly7-2-of-6) in Engine Mechanical - 3.6L (LY7).
8. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using the J 38185 slide the hose clamp down on the hose (3).
3. Disconnect the hose from the auxiliary water pump.
4. Using the J 38185 slide the hose clamp back on the hose (1).
5. Disconnect the hose from the auxiliary water pump.
6. Disconnect the auxiliary water pump electrical connector.
7. Remove the auxiliary water pump nuts.
8. Remove the auxiliary water pump.

1. Install the auxiliary water pump.
2. Install the auxiliary water pump nuts. Tighten: Tighten the nuts to 9 N.m (80 lb in).
3. Connect the auxiliary water pump electrical connector.
4. Connect the hose (3) to the auxiliary water pump.
5. Using the J 38185 slide the hose clamp back into the original position on the hose.
6. Connect the hose (1) to the auxiliary water pump.
7. Using the J 38185 slide the hose clamp back to the original position on the hose.
8. Fill the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using the J 38185 slide the hose clamp down on the hose (3).
3. Disconnect the hose from the afterboil coolant pump.
4. Using the J 38185 slide the hose clamp back on the hose (1).
5. Disconnect the hose from the afterboil coolant pump.
6. Disconnect the afterboil coolant pump electrical connector from the afterboil coolant pump.
7. Remove the afterboil coolant pump nuts.
8. Remove the afterboil coolant pump.

1. Install the afterboil coolant pump.
2. Install the afterboil coolant pump nuts. Tighten: Tighten the nuts to 9 N.m (80 lb in).
3. Connect the afterboil coolant pump electrical connector to the afterboil coolant pump.
4. Connect the hose (3) to the afterboil coolant pump.
5. Using the J 38185 slide the hose clamp back into the original position on the hose.
6. Connect the hose (1) to the afterboil coolant pump.
7. Using the J 38185 slide the hose clamp back to the original position on the hose.
8. Fill the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Lower the vehicle.
3. Disconnect the condenser tube from the fan shroud retainer clip.
4. Remove the cooling fan shroud retaining bolts.
5. Remove the cooling fan shroud.

1. Install the cooling fan shroud.
2. Install the cooling fan shroud retaining bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
3. Connect the condenser tube to the fan shroud retainer clip.
4. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) .
5. Install the fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Disconnect the condenser tube from the fan shroud retainer clip.
3. Remove the cooling fan shroud retaining bolts.
4. Remove the cooling fan shroud.

1. Install the cooling fan shroud.
2. Install the cooling fan shroud retaining bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
3. Connect the condenser tube to the fan shroud retainer clip.
4. Install the fan. Refer to «Fan Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the electric cooling fan. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the upper condenser mounting bolts.
4. Remove the lower condenser mounting bolts.
5. Disconnect the lower retaining pins of the side air baffle from the radiator.
6. Remove the transmission oil cooler (TOC) mounting bolts.
7. Lower the vehicle.
8. Use J 38185 to disengage the tension on the hose clamp. Remove the radiator outlet hose from the radiator.
9. Use J 38185 to disengage the tension on the hose clamp. Remove the radiator inlet hose from the radiator.
10. Use J 38185 to disengage the tension on the hose clamp. Remove the surge tank inlet hose from the radiator.
11. Remove the radiator support bracket bolts.
12. Remove the radiator support brackets.
13. Disconnect the upper air baffle retaining pins from the radiator.
14. Remove the radiator.

1. Install the radiator.
2. Connect the upper air baffle retaining pins to the radiator.
3. Install the radiator support brackets.
4. Install the radiator support bracket bolts. Tighten: Tighten the bolts to 9 N.m (80 lb in).
5. Connect the surge tank inlet hose to the radiator. Use J 38185 to position the surge tank inlet hose clamp to secure the hose.
6. Connect the radiator inlet hose to the radiator. Use J 38185 to position the radiator inlet hose clamp to secure the hose.
7. Connect the radiator outlet hose to the radiator. Use J 38185 to position the radiator outlet hose clamp to secure the hose.
8. Raise and support the vehicle.
9. Install the TOC mounting bolts. Tighten: Tighten the bolts to 5 N.m (44 lb in).
10. Connect the lower retaining pins of the side air baffle to the radiator.
11. Install the lower condenser mounting bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
12. Install the upper condenser mounting bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
13. Install the electric cooling fan. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
14. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the electric cooling fan. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the upper condenser mounting bolts.
4. Remove the lower condenser mounting bolts.
5. Disconnect the lower retaining pins of the side air baffle from the radiator.
6. Remove the transmission oil cooler (TOC) mounting bolts.
7. Lower the vehicle.
8. Remove the fan shroud. Refer to «Fan Shroud Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Shroud Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Use J 38185 to disengage the tension on the hose clamp. Remove the radiator outlet hose from the radiator.
10. Use J 38185 to disengage the tension on the hose clamp. Remove the radiator inlet hose from the radiator.
11. Use J 38185 to disengage the tension on the hose clamp. Remove the surge tank inlet hose from the radiator.
12. Remove the radiator support bracket bolts.
13. Remove the radiator support brackets.
14. Disconnect the upper air baffle retaining pins from the radiator.
15. Remove the radiator.

1. Install the radiator.
2. Connect the upper air baffle retaining pins to the radiator.
3. Install the radiator support brackets.
4. Install the radiator support bracket bolts. Tighten: Tighten the bolts to 9 N.m (80 lb in).
5. Connect the surge tank inlet hose to the radiator. Use J 38185 to position the surge tank inlet hose clamp to secure the hose.
6. Connect the radiator inlet hose to the radiator. Use J 38185 to position the radiator inlet hose clamp to secure the hose.
7. Connect the radiator outlet hose to the radiator. Use J 38185 to position the radiator outlet hose clamp to secure the hose.
8. Install the fan shroud. Refer to «Fan Shroud Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Shroud Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Raise and support the vehicle.
10. Install the TOC mounting bolts. Tighten: Tighten the bolts to 5 N.m (44 lb in).
11. Connect the lower retaining pins of the side air baffle to the radiator.
12. Install the lower condenser mounting bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
13. Install the upper condenser mounting bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
14. Install the electric cooling fan. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
15. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

Radiator Replacement (LY7 Standard Cooling)

Tools Required

1. J 38185 Hose Clamp Pliers
2. J 38778 Door Trim Pad Clip Remover

1. Drain the coolant. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the electric cooling fan assembly. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) .
4. Remove the lower condenser mounting bolts.
5. Remove the upper condenser mounting bolts.
6. Remove the transmission oil cooler mounting bolts.
7. Disconnect the lower retainer pins of the side air baffle from the radiator.
8. Lower the vehicle.
9. Remove the radiator support bracket bolts.
10. Remove the radiator support brackets.
11. Use J 38778 to remove the radiator/condenser upper support.
12. Use J 38185 to disconnect the surge tank inlet hose from the radiator. Reposition the hose aside.
13. Using J 38185 disengage tension on the radiator inlet hose clamp and disconnect the hose from the radiator.
14. Using J 38185 disengage tension on the radiator outlet hose clamp and disconnect the hose from the radiator.
15. Disconnect the upper retainer pins on the side air baffle from the radiator.
16. Remove the radiator.

1. Install the radiator.
2. Connect the upper retainer pins of the side air baffle to the radiator.
3. Connect the radiator outlet hose to the radiator. Use J 38185 to position the radiator outlet hose clamp to secure the hose.
4. Connect the radiator inlet hose to the radiator. Use J 38185 to position the radiator inlet hose clamp to secure the hose.
5. Connect the surge tank inlet hose to the radiator. Use J 38185 to position the hose clamp to secure the hose.
6. Install the radiator/condenser upper support.
7. Install the radiator support brackets.
8. Install the radiator support bracket bolts. Tighten: Tighten the bolts to 9 N.m (80 lb in).
9. Raise and support the vehicle.
10. Connect the lower retainer pins of the side air baffle to the radiator.
11. Install the transmission oil cooler mounting bolts. Tighten: Tighten the bolts to 5 N.m (44 lb in).
12. Install the upper condenser mounting bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
13. Install the lower condenser mounting bolts. Tighten: Tighten the bolts to 5.4 N.m (48 lb in).
14. Lower the vehicle.
15. Install the electric cooling fan assembly. Refer to «Cooling Fan Replacement - Electric (LH2 Standard Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LH2 Heavy Duty Cooling)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .
16. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the radiator support bolts.
2. Remove the radiator support brackets.

1. Install the radiator support brackets.
2. Install the radiator support bolts. Tighten: Tighten the bolts to 9 N.m (80 lb in).

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
2. Disconnect the coolant heater power supply cord from the coolant heater.
3. Complete the following in order to remove the coolant heater from the engine block: Pry outward on the retaining clip. Pull the coolant heater from the engine block.

1. Install the coolant heater into the engine block until the retaining clip is fully engaged.
2. Connect the coolant heater power cord to the coolant heater.
3. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
2. Disconnect the coolant heater power supply cord from the coolant heater.
3. Complete the following in order to remove the coolant heater from the engine block: Pry outward on the retaining clip. Pull the coolant heater from the engine block.

1. Install the coolant heater into the engine block until the retaining clip is fully engaged.
2. Connect the coolant heater power cord to the coolant heater.
3. Lower the vehicle.

1. Turn the ignition OFF.
2. Raise and support the vehicle.
3. Disconnect the coolant heater cord from the coolant heater.
4. Remove the coolant heater.

1. Install the coolant heater.
2. Connect the coolant heater cord to the coolant heater.
3. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
2. Disconnect the coolant heater power supply cord from the coolant heater.
3. Lower the vehicle.
4. Disconnect the coolant heater cord clips from the following: The engine wiring harness conduit The engine oil level indicator tube
5. Remove the coolant heater cord from the vehicle.

1. Position the coolant heater power supply cord to the engine.
2. Route the coolant heater cord along the engine wiring harness conduit.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
4. Connect the coolant heater cord to the coolant heater.
5. Secure the coolant heater cord clip to the coolant heater cord.
6. Lower the vehicle.
7. Secure the coolant heater cord clips to the following: The engine wiring harness conduit The engine oil level indicator tube

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
2. Disconnect the coolant heater power supply cord from the coolant heater (1).
3. Disconnect the coolant heater cord clip (2) from the coolant heater cord.
4. Lower the vehicle.
5. Disconnect the coolant heater cord clips (3, 4) from the following: The engine wiring harness conduit The engine oil level indicator tube
6. Remove the coolant heater cord from the vehicle.

1. Position the coolant heater power supply cord to the engine.
2. Route the coolant heater cord along the engine wiring harness conduit.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
4. Connect the coolant heater cord to the coolant heater (1).
5. Secure the coolant heater cord clip (2) to the coolant heater cord.
6. Lower the vehicle.
7. Secure the coolant heater cord clips (3, 4) to the following: The engine wiring harness conduit The engine oil level indicator tube

Cooling Fan Control - Two Fan System

The engine cooling fan system consists of 2 puller type electrical cooling fans and 3 fan relays. The relays are arranged in a series parallel (S/P) configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood fuse block. The ground path is provided at G104.

During low speed operation, the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the low speed fan relay coil, closes the relay contacts, and supplies battery positive voltage from the low fan fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the cooling fan S/P relay and the right cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. After a 3 second delay, the ECM supplies a ground path for the high speed fan relay and the cooling fan S/P relay through the high speed cooling fan relay control circuit. This energizes the cooling fan S/P relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time, the high speed fan relay coil is energized closing the relay contacts, and provides battery positive voltage from the high fan fuse on the cooling fan motor supply voltage circuit, to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.

The ECM commands the low speed cooling fans ON under the following conditions

1. Engine coolant temperature exceeds approximately 94.5°C (202°F).
2. A/C refrigerant pressure exceeds 1447 kPa (210 psi).
3. After the vehicle is shut OFF, if the engine coolant temperature at key-off is greater than 101°C (214°F), the low speed fans will run for a minimum of 60 seconds. After 60 seconds, if the coolant temperature drops below 101°C (214°F), the fans will shut OFF. The fans will automatically shut OFF after 3 minutes, regardless of coolant temperature.

The ECM commands the high speed fans ON under the following conditions

1. Engine coolant temperature exceeds approximately 104.25°C (220°F).
2. A/C refrigerant pressure exceeds approximately 1824 kPa (265 psi).
3. When certain DTCs set

At idle and very low vehicle speeds the cooling fans are only allowed to increase in speed, if required. This ensures idle stability by preventing the fans from cycling between high and low speed.

Cooling Fan Control - Three Fan System

The engine cooling fan system consists of a mechanical fan, 2 electrical pusher-type cooling fans, and 3 fan relays. The low speed, high speed, and series parallel (S/P) relays are arranged in an S/P configuration that allows the engine control module (ECM) to operate the left cooling fan and right cooling fan together, at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood fuse block. The ground path is provided at G104.

During low speed operation, the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the low speed fan relay coil, closes the relay contacts, and supplies battery positive voltage from the low fan fuse through the cooling fan motor supply voltage circuit, to the left cooling fan. The ground path for the left cooling fan is through the cooling fan S/P relay and the right cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation, the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. After a 3 second delay, the ECM supplies a ground path for the high speed fan relay and the cooling fan S/P relay through the high speed cooling fan relay control circuit. This energizes the cooling fan S/P relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time, the high speed fan relay coil is energized closing the relay contacts, and provides battery positive voltage from the high fan fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.

The ECM commands the low speed fans ON under the following conditions

1. Engine coolant temperature exceeds approximately 94.5°C (202°F).
2. A/C refrigerant pressure exceeds 1447 kPa (210 psi).
3. After the vehicle is shut OFF, if the engine coolant temperature at key-off is greater than 101°C (214°F), the low speed fans will run for a minimum of 60 seconds. After 60 seconds, if the coolant temperature drops below 101°C (214°F), the fans will shut OFF. The fans will automatically shut OFF after 4 minutes, regardless of coolant temperature.

The ECM commands the high speed fans ON under the following conditions

1. Engine coolant temperature exceeds approximately 104.25°C (220°F).
2. A/C refrigerant pressure exceeds 1824 kPa (265 psi).
3. When certain DTCs set

At idle and very low vehicle speeds the cooling fans are only allowed to increase in speed, if required. This ensures idle stability by preventing the fans from cycling between high and low speed.

Engine Coolant

Engine coolant is the key element of the heating system. The engine thermostat controls the normal engine operating coolant temperature. Coolant pumped out of the engine block enters the heater core through the inlet heater hose. The air flowing through the HVAC module absorbs the heat of the coolant flowing through the heater core. The coolant then exits the heater core through the heater outlet hose. To prevent the coolant from boiling after the engine is turned OFF an after-boil/heater coolant pump is used.

The HVAC control module will command the after-boil/heater coolant pump ON, when the engine is OFF, under the following conditions

1. The engine is OFF.
2. The engine coolant temperature is above 101°C (214°F).

The above coolant flow circuits are designed to show the coolant flow related to the coolant by-pass valve positions only. The thermostat function and thermostat coolant flow paths are not shown.

Coolant Warning Messages

The radio will display the following messages if the following conditions exist in the cooling system.

1. Engine hot - A/C OFF will be displayed if coolant temperature is above 117°C (243°F). For imports 115°C (239°F).
2. Engine coolant hot-Idle engine will be displayed if coolant temperature is above 118°C (245°F).
3. Engine overheated-Stop engine will be displayed if coolant temperature is above 123°C (253°F).

Coolant Level Control

The engine cooling system contains an engine coolant level switch to alert the driver in the event of a low coolant level. When the engine coolant level in the surge tank falls below a certain level, the coolant level switch opens. When the HVAC control module detects an open, or a high voltage level on the coolant level indicator control circuit for at least 10 seconds, it will send a class 2 message to the radio requesting display of the low coolant level message. There is approximately a 10 second delay before the HVAC control module sends a class 2 message, to prevent the message from being displayed due to coolant sloshing in the surge tank.

Coolant Heater

The optional engine coolant heater (RPO K05) operates using 110-volt AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather 29°C (20°F). The coolant heater helps reduce fuel consumption when a cold engine is warming up. 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 system maintains an efficient engine operating temperature during all engine speeds and operating conditions. The cooling system removes approximately one-third of the heat produced by the burning of the air-fuel mixture. When the engine is cold, the system cools slowly or not at all, allowing the engine to warm quickly.

Cooling Cycle

The thermostat is located between the radiator outlet and the water pump inlet. At normal operating temperature, coolant is drawn from the radiator outlet and into the water pump inlet by the water pump. In cold conditions, the thermostat bypasses the radiator, and the pump draws coolant directly from the engine outlet.

Coolant is then pumped through the water pump outlet and into the engine block. In the engine block, the coolant circulates through the water jackets surrounding the cylinders and absorbs heat.

The coolant is then forced 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, absorbing additional heat.

Coolant is also directed to the throttle body. There the coolant circulates through passages in the casting. During initial start up, the coolant assists in warming the throttle body. During normal operating temperatures, the coolant assists in keeping the throttle body cool.

From the cylinder heads, the coolant is then forced to the engine outlet. Coolant leaves the engine through 4 different routes

1. Through the engine outlet fitting to the radiator. This path is blocked at cold conditions by the thermostat at the engine inlet fitting.
2. Through the radiator bypass
3. To the heater core for passenger compartment heat and defrost
4. Through the vent hose to the surge tank, providing continuous de-aeration of the cooling system

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 clean drinkable 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, consisting of a core and 2 tanks. The aluminum core is a crossflow tube and fin design. This is a brazed tube with convoluted louvered fin design. Separate tubes and fins are stacked together with a manifold at each end. The entire core assembly is then brazed, forming a homogeneous unified structure. The fins allow for efficient heat transfer from the coolant to the atmosphere. The inlet and outlet tanks are molded with a high temperature, glass reinforced nylon plastic. The tank and gasket is supplied as an assembly with silicone gasket attached to the tank. 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 which is located in the bottom of the passenger side tank. The drain cock includes the drain cock and drain cock seal.

The radiator removes heat from the coolant passing through the radiator. The fins on the core absorb heat from the coolant passing through the tubes. Air passing between the fins absorbs heat and cools the coolant.

During vehicle use, the coolant heats and expands. The coolant that is displaced by this expansion flows into the surge tank. As the coolant circulates, air is allowed to exit. Coolant without bubbles absorbs heat much better than coolant with bubbles.

Pressure Cap

The pressure cap seals and pressurizes the cooling system. The cap contains a blow off or pressure valve and a vacuum or atmospheric valve. The pressure valve is held against the valve seat by a spring which protects the radiator by relieving pressure exceeding 15 psi. The vacuum valve is held against the valve seat by a spring which permits opening of the valve to relieve vacuum created in the cooling system during cooling. The vacuum, if not relieved, could cause the radiator hoses to collapse.

The pressure cap allows pressure in the cooling system to build up. As the pressure builds, the boiling point of the coolant rises as well. Therefore, the coolant can be safely run at a temperature higher than the boiling point of the coolant at atmospheric pressure. The hotter the coolant is, the faster the heat moves from the radiator to the cooler, passing air. However, if the pressure exceeds the strength of the spring, the pressure valve rises so that the excess pressure can escape. When 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 cooling system. This equalizes the pressure in the cooling system with atmospheric pressure, thus preventing the radiator hoses from collapsing.

Surge Tank

The surge tank is a plastic tank with a mounted pressure cap. The tank is mounted at a point higher than all other coolant passages. The surge tank provides an air space in the cooling system. The air space allows the coolant to expand and contract. The surge tank also provides a coolant fill point and a central air bleed location.

During vehicle use, the coolant heats and expands. The coolant that is displaced by this expansion flows into the surge tank. As the coolant circulates, air is allowed to exit. This is an advantage to the cooling system, because coolant without bubbles absorbs heat much better than coolant with bubbles.

Air Baffles and Seals

The cooling system uses deflectors, air baffles, and air seals to increase system cooling. Deflectors are installed under the vehicle which redirect airflow beneath the vehicle to flow through the radiator and increase cooling. Air baffles are also used to direct airflow into the radiator and increase cooling. Air seals prevent air from bypassing the radiator and A/C condenser. Air seals also prevent recirculation of the 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 and an impeller. The impeller is a flat plate mounted on the pump shaft with a series of flat or curved blades or vanes. 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. Its purpose is to regulate the operating temperature of the engine. It utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a piston. When the element is heated, it expands and exerts pressure against a rubber diaphragm. 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 the rated thermostat opening temperature, the thermostat valve remains closed. This prevents circulation of the coolant to the radiator and allows the engine to warm up quickly. After the coolant temperature reaches rated thermostat opening temperature, the thermostat valve will open. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. The thermostat also provides a restriction in the cooling system, even 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 Heat Exchanger

The engine oil heat exchanger is mounted to the top of the engine block, under the intake manifold flange. Oil is pumped through the oil cooler inlet pipe to the heat exchanger, back through the oil cooler outlet pipe, and then to the oil passages in the engine for lubrication. The exchanger provides the following 2 functions

1. Engine coolant warms up faster than the engine oil. During cold operation, the coolant warms the oil and provides better flow during cold engine operation.
2. After the engine reaches normal operating temperature, the engine oil temperature will exceed the engine coolant temperature. The coolant flowing through the engine oil cooler will absorb heat from the engine oil. Cooling the engine oil extends oil life and helps reduce internal engine wear.

Transmission Oil Cooler - V09

Note. The transmission oil cooler system uses quick connect fittings throughout the system. Use a special tool to disconnect these quick connect fittings. Removing the transmission oil cooler lines without this tool will result in damage to the radiator, the transmission, and the transmission oil cooler caused by mixing the transmission oil and coolant or due to transmission oil loss.

The transmission oil cooler (TOC) is an oil-to-water heat exchanger located in the radiator end tank and is non-serviceable. The transmission oil temperature is regulated by the temperature of the coolant leaving the radiator. The oil out of the transmission is plumbed through the TOC lines to the radiator end tank cooler then directed back to the transmission.

Transmission Oil Cooler - V03/V92

Note. The transmission oil cooler system uses quick connect fittings throughout the system. Use a special tool to disconnect these quick connect fittings. Removing the transmission oil cooler lines without this tool will result in damage to the radiator, the transmission, and the transmission oil cooler caused by mixing the transmission oil and coolant or due to transmission oil loss.

The transmission oil cooler (TOC) is an oil-to-air heat exchanger located between the radiator and the A/C condenser. The transmission oil temperature is regulated by the airflow passing over this heat exchanger. The oil out of the transmission is plumbed through the TOC lines to the cooler then directed back to the transmission. This cooler helps provided additional cooling for performance driving conditions.

Transmission Oil Cooler Lines

Note. The transmission oil cooler system uses quick connect fittings throughout the system. Use a special tool to disconnect these quick connect fittings. Removing the transmission oil cooler lines without this tool will result in damage to the radiator, the transmission, and the transmission oil cooler caused by mixing the transmission oil and coolant or due to transmission oil loss.

The transmission oil cooler (TOC) lines use quick connect fittings that must be removed using a special tool. The oil out of the transmission is pumped at a high pressure through the TOC lines to the heat exchanger and then directed back to the transmission.

Power Steering Oil Cooler

Some vehicles are equipped with a power steering oil cooler located either between the radiator and condenser (Heavy Duty) or in front of the engine. This cooler transfers heat from the power steering system to the air passing through the condenser and radiator. The cooler uses constant tension clamps on the hose connections to the cooler.

Special Tools

Special Tools Illustration Tool Number/Description EN 46104 Water Pump Pulley Holding Tool J 23688 Coolant and Battery Fluid Tester J 24460-01 Cooling System Pressure Tester J 24731 Tempilstick 188 J 24731 Tempilstick 206 J 26568 Coolant and Battery Fluid Tester J 38185 Hose Clamp Pliers J 38778 Door Trim Pad Clip Remover J 41240 Fan Clutch Remover and Installer J 42401 Radiator Cap/Surge Tank Test Adapter J 44827 Transmission Cooler Quick Disconnect

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

See also:
• Diagnostic System Check - Vehicle
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Connector Repairs
• Control Module References
• Checking Aftermarket Accessories
• Circuit Testing
• HVAC Control Module Replacement
• Drive Belt Tensioner Diagnosis
• Drive Belt Tensioner Diagnosis
• Drive Belt Tensioner Replacement - Generator and Water Pump
• Drive Belt Tensioner Replacement - Generator
• Heater Core Replacement
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Coolant in Combustion Chamber
• 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
• Cylinder Leakage Test
• Cylinder Leakage Test
• Lifting and Jacking the Vehicle
• Air Deflector Replacement - Front
• Capacities - Approximate Fluid
• Fastener Notice
• Air Cleaner Outlet Duct Replacement
• Air Cleaner Intake Duct Replacement
• Water Outlet Housing Cleaning and Inspection
• Water Pump Cleaning and Inspection
• Engine Cooling Schematics
• Cooling System Connector End Views
• Symptoms - Engine Cooling
• Low Engine Coolant Indicator Always On
• Cooling Fan Always On
• Cooling Fan Inoperative
• Loss of Coolant
• Pressure Cap Testing
• Cooling System Leak Testing
• Special Tools
• Radiator Cleaning
• After Boil Coolant Pump Inoperative
• Fan Clutch Diagnosis
• Radiator Replacement (LY7 Standard Cooling)
• Diagnostic Starting Point - Engine Cooling
• Fastener Tightening Specifications
• Flushing