Engine Cooling System Buick Rendezvous I

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 1

Scheme 2

Scheme 3

Cooling System Connector End Views

Cooling Fan Connector End - Left Connector Part Information 12033769 2-Way F Metri-Pack 630 Series Sealed P2S (BK) Pin Wire Color Circuit No. Function A WH 504 Cooling Fan Motor Ground (LA1) RD 504 Cooling Fan Motor Ground (LY7) B GY 532 Cooling Fan Motor Supply Voltage (LA1) BK 532 Cooling Fan Motor Supply Voltage (LY7)

Cooling Fan Connector End - Right Connector Part Information 12033769 2-Way F Metri-Pack 630 Series Sealed P2S (BK) Pin Wire Color Circuit No. Function A BK 1250 Ground (LA1) RD 1250 Ground (LY7) B L- BU 409 Cooling Fan Motor Supply Voltage (LA1) BK 409 Cooling Fan Motor Supply Voltage (LY7)

Diagnostic Starting Point - Engine Cooling

Begin the system diagnosis with the Diagnostic System Check - Engine Cooling . The Diagnostic System Check will provide the following information

1. The identification of the control module(s) which command the system.
2. The ability of the control module(s) 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.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. 2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
2. 3: Determine if the Instrument Cluster or Powertrain Control Modules have set DTC's which may affect Engine Cooling operation are present.
3. 4: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Diagnostic System Check - Engine Cooling

Scan Tool Output Controls

Powertrain Control Module (PCM) 3.4 Liter LA1 Scan Tool Output Control

Engine Control Module (ECM) 3.6L LY7 Scan Tool Output Control

Scan Tool Data List

Powertrain Control Module Scan Tool Data List (PCM) 3.4 Liter LA1

Engine Control Module Scan Tool Data List (ECM) 3.6L LY7

Diagnostic Trouble Code (DTC) List

Diagnostic Trouble Code (DTC) List

Circuit Description

Battery positive voltage is supplied to the cooling fan 1 relay from the COOL FAN #1 fuse. The powertrain control module (PCM) or engine control module (ECM) controls the cooling fan 1 relay by grounding the low speed cooling fan relay control circuit via an internal solid state device called a driver.

Battery positive voltage is supplied to the cooling fan 2 relay and the cooling fan 3 or S/P relay from the COOL FAN #2 fuse. The PCM/ECM controls the relays by grounding the high speed cooling fan relay control circuit.

When the PCM/ECM is commanding a relay on, the voltage potential of the control circuit should be low, near 0 volts. When the PCM/ECM is commanding the control circuit to a relay, the voltage potential of the circuit should be high, near battery voltage. If the fault detection circuit senses a voltage other than what is expected, the DTC will set.

The PCM/ECM will monitor the control circuit for the following

1. A short to ground
2. A short to voltage
3. An open circuit
4. An open relay coil
5. An internally shorted or excessively low resistance relay coil

When the PCM/ECM detects any of the above conditions, the DTC will set and the affected driver will be disabled.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P0480 Cooling Fan 1 Relay Control Circuit
2. DTC P0481 Cooling Fan 2 and 3 or S/P Relay Control Circuit
3. DTC P0691 Cooling Fan 1 relay Control Circuit Low Voltage
4. DTC P0692 Cooling Fan 1 Relay Control Circuit High Voltage
5. DTC P0693 Cooling Fan 2 and 3 or S/P Relay Control Circuit Low Voltage
6. DTC P0694 Cooling Fan 2 and 3 or S/P Relay Control Circuit High Voltage

Conditions for Running the DTC

1. The ignition is ON.
2. System voltage is between 9-18 volts.
3. The relay control circuit is transitioned from OFF to ON or ON to OFF.

Conditions for Setting the DTC

1. The PCM/ECM detects an open, a short to ground or a short to voltage on the cooling fan relay control circuit.
2. The above conditions are present for at least 30 seconds.

Action Taken When the DTC Sets

1. The PCM/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 PCM/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 PCM/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. The DTC can be cleared by using the scan tool.

Diagnostic Aids

1. If the condition is not present, refer to «Testing for Intermittent Conditions and Poor Connections»(/buick/rendezvous/i-2001-2007/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. Review the Freeze/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

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

1. 2: Listen for an audible click when the cooling fan 1 relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3: Listen for an audible click when the cooling fan 2 and cooling fan 3 or S/P relays operate. Command both the ON and OFF states. Repeat the commands as necessary.
3. 4: Tests for voltage at the coil side of the cooling fan 1 relay. The COOL FAN #1 fuse supplies battery positive voltage to the coil side of the cooling fan 1 relay.

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

The powertrain control module (PCM) or engine control module (ECM) uses the 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 PCM/ECM will disable 2 groups of 4 cylinders by turning OFF the fuel injectors. By switching between the 2 groups of cylinders, the PCM/ECM is able to reduce the temperature of the coolant.

The ignition is ON.

1. The PCM/ECM detects an engine metal over temperature.
2. The above condition is present for at least 8 seconds.

1. The PCM/ECM will illuminate the malfunction indicator Lamp (MIL) during the first trip in which the diagnostic test has been run and failed.
2. The PCM/ECM will signal the IPC to turn ON the Service Engine Soon indicator.
3. The PCM/ECM will alternately disable 2 groups of four cylinders by turning OFF the fuel injectors.
4. The PCM/ECM will store conditions which were present when the DTC set as Freeze Frame and File Records data.
5. A history DTC is stored.

1. The PCM/ECM will turn the MIL OFF after three 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»(/buick/rendezvous/i-2001-2007/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__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. «Engine Coolant Temperature Indicator Always On»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system__engine-coolant-temperature-indicator-always-on)
2. «Cooling Fan Always On»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system__cooling-fan-always-on)
3. «Cooling Fan Inoperative»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system__cooling-fan-inoperative)
4. «Coolant Heater Inoperative»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system__coolant-heater-inoperative)
5. «Engine Overheating»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system__engine-overheating)
6. «Loss of Coolant»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system__loss-of-coolant)
7. «Thermostat Diagnosis»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system)
8. «Engine Fails To Reach Normal Operating Temperature»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system__engine-fails-to-reach-normal-operating)

Engine Coolant Temperature Indicator Always On

Engine Coolant Temperature Indicator Always On

Cooling Fan Always On

Cooling Fan Always On

Cooling Fan Inoperative

Cooling Fan Inoperative

Engine Overheating

Engine Overheating

Loss of Coolant

Loss of Coolant

Tools Required

J 24731 Tempil Stick. See Special Tools and Equipment .

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

Thermostat Test Procedure Using Tempil Sticks

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

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

Coolant Heater Inoperative

Coolant Heater Inoperative

Engine Fails To Reach Normal Operating Temperature

Engine Fails To Reach Normal Operating Temperature

J 24460-01 Cooling System Pressure Tester. See Special Tools and Equipment .

Test Procedure

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the J 24460-01 in order to test the pressure cap. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
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 and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) . 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.

J 24460-01 Cooling System Pressure Tester. See Special Tools and Equipment .

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Wash the pressure cap mating surface with water.
4. Use the J 24460-01 in order to apply pressure to the cooling system. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) . 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.

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

Draining Procedure

1. Remove the coolant pressure cap.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Place a drain pan under the drain cock.
4. Open the radiator drain cock.
5. Drain the cooling system.
6. If a complete engine block drain is required LA1 engine, remove the engine block drain plugs.
7. If a complete engine block drain is required LY7 engine, remove the starter motor. Refer to «Starter Motor Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
8. If a complete engine block drain is required LY7 engine, remove the engine block drain plugs.
9. Inspect the coolant.
10. Follow the appropriate procedure based on the condition of the coolant. Normal in appearance - follow the filling procedure. Discolored - follow the flush procedure. Refer to: «Flushing»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

Filling Procedure

1. Close the radiator drain cock.
2. If the engine block drain plugs were removed from the LA1 or LY7 engine, perform the following: Apply pipe sealer to the drain plugs. Install the drain plugs. Tighten: Tighten the drain plugs to 22 N.m (16 lb ft).
3. If the engine block was drained LY7 engine, install the starter motor. Refer to «Starter Motor Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
4. Lower the vehicle.
5. Open the cooling system bleeder screws.
6. Slowly fill the cooling system with a 50/50 coolant mixture. Refer to «Capacities - Approximate Fluid»(/buick/rendezvous/i-2001-2007/remont/lubrication-system/#maintenance-and-lubrication__capacities-approximate-fluid) .
7. Close the cooling system bleeder screws.
8. Install the coolant pressure cap.
9. Start the engine.
10. Run the engine at 2000 - 2500 RPM until the engine reaches normal operating temperature.
11. Allow the engine to idle for 3 minutes.
12. Shut the engine off.
13. Allow the engine to cool.
14. Top off the coolant as necessary.
15. Inspect the concentration of the engine coolant. Using the J 26568 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
16. Rinse away any excess coolant from the engine and the engine compartment.

Flushing Procedure

Store used coolant in the proper manner, such as in a used engine coolant holding tank. Do not pour used coolant down a drain. Ethylene glycol antifreeze is a very toxic chemical. Do not dispose of coolant into the sewer system or ground water. This is illegal and ecologically unsound.

Various methods and equipment can be used to flush the cooling system. If special equipment is used, such as a back flusher, follow the manufacturer's instruction. Always remove the thermostat before flushing the cooling system.

When the cooling system becomes contaminated, the cooling system should be flushed thoroughly to remove the contaminants before the engine is seriously damaged.

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Clean and flush the coolant recovery reservoir with clean, drinkable water.
4. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Follow the drain and fill procedure using only clean, drinkable water. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
6. Run the engine for 20 minutes.
7. Stop the engine.
8. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
9. Repeat the procedure if necessary, until the fluid is nearly colorless.
10. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#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. See Special Tools and Equipment .

Removal Procedure

1. Reposition the reservoir hose clamp at the radiator overflow fitting using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the reservoir hose at the radiator overflow fitting.
3. Remove the reservoir mounting clip.
4. Remove the coolant reservoir.

Installation Procedure

1. Install the coolant reservoir.
2. Install the reservoir mounting clip.
3. Connect the reservoir hose to the radiator overflow fitting.
4. Reposition the reservoir hose clamp to secure the hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Fill the coolant reservoir. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Reposition the hose clamp at the radiator using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Disconnect the radiator inlet hose from the radiator.
4. Reposition the hose clamp at the thermostat housing using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Disconnect the radiator inlet hose from the thermostat housing.
6. Remove the radiator inlet hose.

1. Install the radiator inlet hose.
2. Connect the radiator inlet hose to the radiator.
3. Reposition the hose clamp at the radiator to secure the hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Connect the radiator inlet hose to the thermostat housing.
5. Reposition the hose clamp at the thermostat housing to secure the hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Use J 38185 to reposition the hose clamp at the radiator. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Disconnect the radiator inlet hose from the radiator.
4. Use J 38185 to reposition the hose clamp at the engine. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Disconnect the radiator inlet hose from the engine.
6. Remove the radiator inlet hose.

1. Install the radiator inlet hose.
2. Connect the radiator inlet hose to the radiator.
3. Using J 38185 , reposition the hose clamp at the radiator to secure the hose. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Connect the radiator inlet hose to the engine.
5. Using J 38185 , reposition the hose clamp at the engine to secure the hose. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Reposition the hose clamp at the water pump housing using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Disconnect the radiator outlet hose from the water pump housing.
4. Reposition the hose clamp at the radiator using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Disconnect the radiator outlet hose from the radiator.
6. Remove the radiator outlet hose.

1. Install the radiator outlet hose.
2. Connect the radiator outlet hose to the radiator.
3. Reposition the hose clamp at the radiator to secure the hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Connect the radiator outlet hose to the water pump housing.
5. Reposition the hose clamp at the water pump housing to secure the hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Use J 38185 to reposition the hose clamp at the engine. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Disconnect the radiator outlet hose from the engine.
4. Use J 38185 to reposition the hose clamp at the radiator. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Disconnect the radiator outlet hose from the radiator.
6. Remove the radiator outlet hose.

1. Install the radiator outlet hose.
2. Connect the radiator outlet hose to the radiator.
3. Using J 38185 , reposition the hose clamp at the radiator to secure the hose. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Connect the radiator outlet hose to the engine.
5. Using J 38185 , reposition the hose clamp at the engine to secure the hose. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
6. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Remove the air cleaner duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.
2. Remove the throttle cable bracket in order to gain access to the throttle body heater hose clamp.
3. Drain the coolant until the coolant level is below the throttle body heater hoses. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Use the J 38185 in order to remove the hose clamp. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Remove the throttle body heater inlet hose.

1. Install the throttle body heater inlet hose.
2. Use the J 38185 in order to install the hose clamps. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Install the throttle cable bracket.
4. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Install the air cleaner duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Remove the air cleaner duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.
2. Drain the coolant until the coolant level is below the throttle body heater hoses. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Use the J 38185 in order to remove the hose clamp. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Remove the throttle body heater outlet hose.

1. Install the throttle body heater outlet hose.
2. Use the J 38185 in order to install the hose clamps. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Install the air cleaner duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.

1. Turn the ignition off.
2. Remove the cooling fans with the cooling fan shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove the cooling fan nut.
4. Remove the cooling fan.

1. Install the cooling fan.
2. Install the cooling fan nut. Tighten: Tighten the nut to 6 N.m (53 lb in).
3. Install the cooling fans with the cooling fan shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Remove the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.
2. Remove the cooling fan harness electrical connector.
3. Remove right side diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal - Right»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
4. Loosen the engine mount strut nuts.
5. Remove the engine mount strut bracket brace bolts from the upper radiator support and rotate the struts and brackets rearward.
6. Remove upper radiator hose. Refer to «Radiator Hose Replacement - Inlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system)
7. Remove the radiator upper mount bolts (1).
8. Remove the radiator upper mounts.
9. Remove the cooling fan shroud bolts.
10. Reposition the coolant overflow hose clamp at the radiator using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
11. Disconnect and reposition the coolant overflow hose.
12. Disconnect the upper TOC line from the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
13. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
14. Disconnect the TOC lines from the fan module retainer clip.
15. Lower the vehicle.
16. Disconnect the engine wiring harness retainers at the engine harness bracket.
17. Reposition the engine wiring harness.
18. Remove the cooling fans with the cooling fan shroud.

1. Install the cooling fans with the cooling fan shroud.
2. Reposition the engine wiring harness.
3. Connect the engine wiring harness retainers at the engine harness bracket.
4. Raise the vehicle.
5. Connect the TOC lines to the fan module retainer clip.
6. Lower the vehicle.
7. Connect the upper TOC line to the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
8. Install the cooling fan shroud bolts. Tighten: Tighten the bolts to 6 N.m (53 lb in).
9. Install the radiator upper mounts.
10. Install the radiator upper mount bolts (1). Tighten: Tighten the bolts to 10 N.m (88 lb in).
11. Install the coolant overflow hose to the radiator.
12. Reposition the hose clamp to secure the coolant overflow hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
13. Install the upper radiator hose. Refer to «Radiator Hose Replacement - Inlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
14. Position the engine mount struts brackets flush with the upper radiator support.
15. Install the engine mount strut bracket brace bolts to the upper radiator support. Tighten: Tighten bolts to 28 N.m (21 lb ft).
16. Tighten the engine mount strut nuts. Tighten: Tighten the nuts to 48 N.m (35 lb ft).
17. Install right side diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal - Right»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
18. Install the cooling fan harness electrical connector.
19. Install the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Remove the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) in Engine Controls - 3.6L.
2. Disconnect the electrical connector from the cooling fan harness.
3. Remove right side diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal - Right»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
4. Loosen the engine mount strut nuts. Do NOT remove the nuts.
5. Remove the bracket brace bolts for the engine mount strut from the upper radiator support. Rotate the struts and brackets rearward.
6. Remove upper radiator hose. Refer to «Radiator Hose Replacement - Inlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
7. Remove the radiator upper mount bolts (1).
8. Remove the radiator upper mounts.
9. Remove the cooling fan shroud bolts.
10. Use J 38185 to reposition the coolant overflow hose clamp at the radiator. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
11. Disconnect and reposition the coolant overflow hose.
12. Disconnect the upper transmission oil cooler (TOC) line from the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
13. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
14. Disconnect the TOC lines from the fan module retainer clip.
15. Lower the vehicle.
16. Disconnect the engine wiring harness retainers at the engine harness bracket.
17. Reposition the engine wiring harness.
18. Remove the cooling fans with the cooling fan shroud.

1. Install the cooling fans with the cooling fan shroud.
2. Reposition the engine wiring harness.
3. Connect the engine wiring harness retainers at the engine harness bracket.
4. Raise the vehicle.
5. Connect the TOC lines to the fan module retainer clip.
6. Lower the vehicle.
7. Connect the upper TOC line to the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
8. Install the cooling fan shroud bolts. Tighten: Tighten the bolts to 6 N.m (53 lb in).
9. Install the radiator upper mounts.
10. Install the radiator upper mount bolts (1). Tighten: Tighten the bolts to 10 N.m (88 lb in).
11. Install the coolant overflow hose to the radiator.
12. Using J 38185 , reposition the hose clamp to secure the coolant overflow hose. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
13. Install the upper radiator hose. Refer to «Radiator Hose Replacement - Inlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
14. Position the engine mount struts brackets flush with the upper radiator support.
15. Install the brace bolts to secure the engine mount strut bracket with the upper radiator support. Tighten: Tighten bolts to 28 N.m (21 lb ft).
16. Install the engine mount strut nuts. Tighten: Tighten the nuts to 48 N.m (35 lb ft).
17. Install right side diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal - Right»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
18. Connect the cooling fan harness electrical connector.
19. Install the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) in Engine Controls - 3.6L.

1. Turn the ignition off.
2. Remove the cooling fan and shroud assembly. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove the cooling fan nut.
4. Remove the cooling fan from the shroud.
5. Disconnect the electrical connector from the cooling fan motor.
6. Remove the screws from the cooling fan motor.
7. Remove the cooling fan motor.

1. Install the cooling fan motor.
2. Install the screws to the cooling fan motor. Tighten: Tighten the screws to 6 N.m (53 lb in).
3. Connect the electrical connector to the cooling fan motor.
4. Install the cooling fan to the shroud.
5. Install the cooling fan nut. Tighten: Tighten the nut to 6 N.m (53 lb in).
6. Install the cooling fan and shroud assembly. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Remove the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.
2. Drain the coolant until the coolant level is below the thermostat. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove the crossover exhaust pipe. Refer to «Exhaust Crossover Pipe Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
4. Remove the radiator hose from the thermostat housing.
5. Remove the thermostat housing bolts and clean any sealer from the bolt threads.
6. Remove the thermostat housing and gasket.
7. Remove the thermostat.
8. Clean the mating surfaces.

1. Install the thermostat.
2. Install the thermostat housing and gasket.
3. Install the thermostat housing bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
4. Install the radiator hose to the thermostat housing.
5. Install the crossover exhaust pipe. Refer to «Exhaust Crossover Pipe Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
6. Install the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.
7. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Remove the air cleaner. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) in Engine Controls-3.6L (LY7).
2. Remove the throttle body assembly. Refer to «Throttle Body Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
3. Remove the heater pipes. Refer to «Heater Pipes Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
4. Remove the coolant inlet pipe. Refer to «Coolant Pipe Replacement - Inlet»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Remove the thermostat bolts and the thermostat.
6. Clean the thermostat and heater pipe sealing surfaces.

1. Install a NEW thermostat gasket.
2. Install the thermostat and gasket.
3. Install the thermostat bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
4. Install the coolant inlet pipe. Refer to «Coolant Pipe Replacement - Inlet»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Install the heater pipes. Refer to «Heater Pipes Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
6. Install the throttle body assembly. Refer to «Throttle Body Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
7. Install the air cleaner. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) in Engine Controls-3.6L (LY7).
8. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Remove the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls-3.4L.
2. Drain the coolant until the coolant level is below the thermostat. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove the crossover exhaust pipe. Refer to «Exhaust Crossover Pipe Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
4. Remove the radiator hose from the thermostat housing.
5. Remove the thermostat housing bolts and clean any sealer from the bolt threads.
6. Remove the thermostat housing and gasket.
7. Remove the thermostat.
8. Clean the mating surfaces.

1. Install the thermostat.
2. Install the thermostat housing and gasket.
3. Install RTV sealer (GM P/N 1052366 or the equivalent) to the thermostat housing bolt threads.
4. Install the thermostat housing bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
5. Install the radiator hose to the thermostat housing.
6. Install the crossover exhaust pipe. Refer to «Exhaust Crossover Pipe Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
7. Install the air cleaner and duct assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls-3.4L.
8. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Drain the coolant until the coolant level is below the water outlet. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the upper radiator hose from the water outlet. Refer to «Radiator Hose Replacement - Inlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove and reposition the power steering pressure hose and the power steering reservoir from the water outlet. Refer to «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
4. Remove the water outlet bolts and the water outlet.
5. Remove and discard the water outlet seals.
6. Clean the water outlet sealing surfaces.

1. Install the NEW water outlet seals.
2. Install the water outlet and the water outlet bolts. Tighten: Tighten the water outlet bolts to 10 N.m (89 lb in).
3. Install the power steering reservoir and the power steering pressure hose bracket to the water outlet. Refer to «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
4. Install the upper radiator hose to the water outlet. Refer to «Radiator Hose Replacement - Inlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Drain the coolant until the coolant level is below the lower radiator hose. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the lower radiator hose from the coolant inlet pipe. Refer to «Radiator Hose Replacement - Outlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove the water coolant inlet pipe bolts and the coolant inlet pipe.
4. Remove and discard the coolant inlet pipe seal.

1. Install the NEW coolant inlet pipe seal.
2. Install the coolant inlet pipe bolts. Tighten Tighten the water outlet upper bolt (2) to 23 N.m (17 lb ft). Tighten the water outlet lower bolt (1) to 50 N.m (37 lb ft).
3. Install the lower radiator hose to the coolant inlet pipe. Refer to «Radiator Hose Replacement - Inlet (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Radiator Hose Replacement - Inlet (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools and Equipment .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the spark plug wire harness from the thermostat bypass pipe.
3. Remove the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.
4. Remove the upper radiator hose from the thermostat housing.
5. Disconnect the left engine mount strut from the engine.
6. Remove the heater hose from the bypass pipe.
7. Remove the thermostat bypass pipe to throttle body nut.
8. Use the J 38185 in order to remove the thermostat bypass pipe hose clamps (1,5). See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
9. Remove the thermostat bypass pipe to cylinder head nut (3).
10. Remove the thermostat bypass pipe bolt (4).
11. Remove the thermostat bypass pipe hose.
12. Remove the thermostat bypass pipe.

1. Apply engine coolant to the bypass pipe seal in order to ease installation.
2. Install the thermostat bypass pipe.
3. Install the thermostat bypass pipe hose.
4. Install the thermostat bypass pipe hose clamp (5).
5. Install the thermostat bypass pipe bolt (4). Tighten: Tighten the thermostat bypass pipe bolt to 11 N.m (98 lb in).
6. Install the thermostat bypass pipe to cylinder head nut (3). Tighten: Tighten the thermostat bypass pipe nut to 25 N.m (18 lb ft).
7. Install the thermostat bypass pipe to throttle body hose clamps (1).
8. Install the thermostat bypass pipe to throttle body nut. Tighten: Tighten the thermostat bypass pipe nut to 25 N.m (18 lb ft).
9. Install the heater hose to the bypass pipe.
10. Install the left engine mount strut to the engine.
11. Install the upper radiator hose to the engine.
12. Install the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) in Engine Controls - 3.4L.
13. Install the spark plug wire harness to the thermostat bypass pipe.
14. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Drain the cooling system until the coolant is below the level of the water pump. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the drive belt guard.
3. Loosen the water pump pulley bolts.
4. Remove the drive belt. Refer to «Drive Belt Replacement»(/buick/rendezvous/i-2001-2007/remont/mechanical/#engine-mechanical-34l-la1) in Engine Mechanical - 3.4L.
5. Remove the water pump pulley bolts.
6. Remove the water pump pulley.
7. Remove the water pump bolts.
8. Remove the water pump.
9. Remove the water pump gasket.
10. Clean the water pump mating surfaces.

1. Install the water pump gasket.
2. Install the water pump.
3. Install the water pump bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
4. Install the water pump pulley.
5. Install the water pump pulley bolts.
6. Install the drive belt. Refer to «Drive Belt Replacement»(/buick/rendezvous/i-2001-2007/remont/mechanical/#engine-mechanical-34l-la1) in Engine Mechanical - 3.4L. Tighten: Tighten the water pump pulley bolts to 25 N.m (18 lb in).
7. Install the drive belt guard.
8. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

EN 46104 Water Pump Pulley Holding Tool

1. Drain the cooling system until the coolant is below the water pump. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the accessory drive belt from the water pump. Refer to «Drive Belt Replacement»(/buick/rendezvous/i-2001-2007/remont/mechanical/#engine-mechanical-repair-instructions-1-of-5-36l-ly7) in Engine Mechanical - 3.6L (LY7).
3. Use the EN 46104 in order to retain the water pump pulley.
4. Remove the water pump pulley bolts and the water pump pulley.
5. Remove the water pump bolts.
6. Remove the water pump.
7. Remove and discard the water pump gasket.
8. Clean the water pump sealing surfaces.

1. Install the NEW water pump gasket.
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.
5. Use the EN 46104 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 accessory drive belt. Refer to «Drive Belt Replacement»(/buick/rendezvous/i-2001-2007/remont/mechanical/#engine-mechanical-repair-instructions-1-of-5-36l-ly7) in Engine Mechanical - 3.6L (LY7).
8. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Remove the cooling fan assembly including the shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the cooling fan nuts.
3. Remove the cooling fans from the shroud.
4. Disconnect the fan motor electrical connectors.
5. Remove the fan motor screws.
6. Remove the fan motors from the cooling fan shroud.
7. Remove the heat shields from the cooling fan shroud.

1. Install the heat shields to the cooling fan shroud.
2. Install the fan motors to the cooling fan shroud.
3. Install the screws to the cooling fan motor. Tighten: Tighten the screws to 6 N.m (53 lb in).
4. Connect the cooling fan motor electrical connectors.
5. Install the cooling fans to the shroud.
6. Install the cooling fan nuts. Tighten: Tighten the nuts to 6 N.m (53 lb in).
7. Install the cooling fan assembly including the shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Remove the cooling fan assembly including the shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Remove the cooling fan nuts.
3. Remove the cooling fans from the shroud.
4. Disconnect the fan motor electrical connectors.
5. Remove the fan motor screws.
6. Remove the fan motors and the heat shields from the cooling fan shroud.

1. Install the fan motors and the heat shields to the cooling fan shroud.
2. Install the screws to the cooling fan motor. Tighten: Tighten the screws to 6 N.m (53 lb in).
3. Connect the cooling fan motor electrical connectors.
4. Install the cooling fans to the shroud.
5. Install the cooling fan nuts. Tighten: Tighten the nuts to 6 N.m (53 lb in).
6. Install the cooling fan assembly including the shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

Radiator Replacement (LA1)

Tools Required

1. J 38185 Hose Clamp Pliers. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. J 39400-A Halogen Leak Detector. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) in Heating, Ventilation and Air Conditioning.
2. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove the cooling fans with the cooling fan shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Reposition the hose clamp at the water pump housing using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Disconnect the radiator outlet hose from the water pump housing.
6. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
7. Reposition the hose clamp at the radiator using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
8. Disconnect the radiator outlet hose from the radiator.
9. Remove the radiator outlet hose.
10. Disconnect the lower TOC line from the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
11. Lower the vehicle.
12. Remove the nut which secures the A/C discharge hose to the condenser block.
13. Disconnect the A/C discharge hose from the condenser block.
14. Remove and discard the sealing washer.
15. Cap or tape off the A/C discharge hose.
16. Remove the bolt which secures the evaporator inlet tube to the condenser block.
17. Disconnect the evaporator inlet tube from the condenser block.
18. Cap or tape off the evaporator inlet tube.
19. Remove the radiator and condenser assembly.
20. Remove the condenser tube clip bolt.
21. Remove the condenser mounting bolts.
22. Remove the condenser from the radiator.

1. Install the condenser to the radiator.
2. Install the mounting bolts that secure the condenser to the radiator. Tighten: Tighten the bolts to 6 N.m (53 lb in).
3. Install the condenser tube clip bolt. Tighten: Tighten the bolt to 2.5 N.m (22 lb in).
4. Install the radiator and condenser assembly.
5. Remove the cap or the tape from the evaporator inlet tube.
6. Install a new seal washer to the evaporator inlet tube. Refer to «Sealing Washer Replacement»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Install the evaporator inlet tube and the bolt to the condenser block. Tighten: Tighten bolt to 16 N.m (12 lb ft).
8. Remove the cap or the tape from the A/C discharge hose.
9. Install a new sealing washer to the A/C discharge hose. Refer to «Sealing Washer Replacement»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
10. Install the A/C discharge hose and the nut to the condenser block. Tighten: Tighten the nut to 16 N.m (12 lb ft).
11. Raise the vehicle.
12. Connect the lower TOC line to the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
13. Install the radiator outlet hose.
14. Connect the radiator outlet hose to the radiator.
15. Reposition the hose clamp at the radiator to secure the hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
16. Lower the vehicle.
17. Connect the radiator outlet hose to the water pump housing.
18. Reposition the hose clamp at the water pump housing to secure the hose using the J 38185 . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
19. Install the cooling fans with the cooling fan shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
20. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
21. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) in Heating, Ventilation and Air Conditioning.
22. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
23. Inspect the transmission fluid level. Refer to «Transmission Fluid Checking Procedure»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-ediagnostics-troubleshooting__transmission-fluid-checking-procedure) in Automatic Transaxle - 4T65-E.

Radiator Replacement (LY7)

Tools Required

1. J 38185 Hose Clamp Pliers. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. J 39400-A Halogen Leak Detector. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) in Heating, Ventilation and Air Conditioning.
2. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
3. Remove the cooling fans with the cooling fan shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
4. Use J 38185 to reposition the hose clamp at the engine. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
5. Disconnect the radiator outlet hose from the engine.
6. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
7. Use J 38185 to reposition the hose clamp at the radiator. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
8. Disconnect the radiator outlet hose from the radiator.
9. Remove the radiator outlet hose.
10. Disconnect the lower TOC line from the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
11. Lower the vehicle.
12. Remove the nut which secures the A/C discharge hose to the condenser block.
13. Disconnect the A/C discharge hose from the condenser block.
14. Remove and discard the sealing washer.
15. Cap or tape off the A/C discharge hose.
16. Remove the bolt which secures the evaporator inlet tube to the condenser block.
17. Disconnect the evaporator inlet tube from the condenser block.
18. Cap or tape off the evaporator inlet tube.
19. Remove the radiator and condenser assembly.
20. Remove the condenser tube clip bolt.
21. Remove the condenser mounting bolts.
22. Remove the condenser from the radiator.

1. Install the condenser to the radiator.
2. Install the mounting bolts that secure the condenser to the radiator. Tighten: Tighten the bolts to 6 N.m (53 lb in).
3. Install the condenser tube clip bolt. Tighten: Tighten the bolt to 2.5 N.m (22 lb in).
4. Install the radiator and condenser assembly.
5. Remove the cap or the tape from the evaporator inlet tube.
6. Install a new seal washer to the evaporator inlet tube. Refer to «Sealing Washer Replacement»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Install the evaporator inlet tube and the bolt to the condenser block. Tighten: Tighten bolt to 16 N.m (12 lb ft).
8. Remove the cap or the tape from the A/C discharge hose.
9. Install a new sealing washer to the A/C discharge hose. Refer to «Sealing Washer Replacement»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
10. Install the A/C discharge hose and the nut to the condenser block. Tighten: Tighten the nut to 16 N.m (12 lb ft).
11. Raise the vehicle.
12. Connect the lower TOC line to the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-service-replacement) in Automatic Transaxle - 4T65-E.
13. Install the radiator outlet hose.
14. Connect the radiator outlet hose to the radiator.
15. Using J 38185 , reposition the hose clamp at the radiator to secure the hose. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
16. Lower the vehicle.
17. Connect the radiator outlet hose to the engine
18. Using J 38185 , reposition the hose clamp at the engine to secure the hose. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
19. Install the cooling fans with the cooling fan shroud. Refer to «Cooling Fan Replacement - Electric (LA1)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) or «Cooling Fan Replacement - Electric (LY7)»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
20. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
21. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/buick/rendezvous/i-2001-2007/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) in Heating, Ventilation and Air Conditioning.
22. Using J 39400-A , leak test the fittings of the component. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
23. Inspect the transmission fluid level. Refer to «Transmission Fluid Checking Procedure»(/buick/rendezvous/i-2001-2007/remont/automatic-trans/#automatic-transaxle-4t65-ediagnostics-troubleshooting__transmission-fluid-checking-procedure) in Automatic Transaxle - 4T65-E.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the air baffle bolts.
3. Remove the air baffle.

1. Install the air baffle.
2. Install the air baffle bolts. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
3. Lower the vehicle.

1. Drain the engine cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the right front wheel. Refer to «Tire and Wheel Removal and Installation»(/buick/rendezvous/i-2001-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
4. Remove the right engine splash shield. Refer to «Splash Shield Replacement - Engine»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
5. Remove the engine coolant heater cord from the engine coolant heater.
6. Loosen the coolant heater bolt.
7. Remove the coolant heater.

1. Apply GM P/N United States 12346004, GM P/N Canada 10953480 or equivalent to the coolant heater seal and the coolant heater hole.
2. Ensure that the coolant heater element is horizontal and pointed toward the front of the engine. The 3 o'clock position (2) is DESIRED. The 2 o'clock position (1) and the 4 o'clock position (3) are acceptable.
3. Install the coolant heater.
4. Install the coolant heater bolt. Tighten: Tighten the bolt to 2 N.m (18 lb in).
5. Install the engine coolant heater cord to the engine coolant heater.
6. Install the right engine splash shield. Refer to «Splash Shield Replacement - Engine»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
7. Install the right front wheel. Refer to «Tire and Wheel Removal and Installation»(/buick/rendezvous/i-2001-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
8. Lower the vehicle.
9. Fill the engine cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the catalytic converter. Refer to «Catalytic Converter Replacement»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
3. Remove the engine coolant heater cord from the engine coolant heater.
4. Remove the coolant heater.

1. Install the coolant heater.
2. Install the engine coolant heater cord to the engine coolant heater.
3. Install the catalytic converter. Refer to «Catalytic Converter Replacement»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
4. Lower the vehicle.

1. Press the coolant heater strap retainer tab in order to remove coolant heater cord strap.
2. Use wire cutters in order to remove the remaining coolant heater cord straps from the engine wiring harness.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Use wire cutters in order to remove the 3 coolant heater cord lower straps (1) from the engine wiring harness.
5. Remove the right front wheel. Refer to «Tire and Wheel Removal and Installation»(/buick/rendezvous/i-2001-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
6. Remove the right engine splash shield. Refer to «Splash Shield Replacement - Engine»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
7. Remove the engine coolant heater cord from the engine coolant heater.
8. Remove the engine coolant heater cord.

1. Install the engine coolant heater cord to the engine coolant heater.
2. Properly route the coolant heater cord.
3. Install new tie straps (1) in order to secure the coolant heater cord to the engine wiring harness.
4. Install the right engine splash shield. Refer to «Splash Shield Replacement - Engine»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
5. Install the right front wheel. Refer to «Tire and Wheel Removal and Installation»(/buick/rendezvous/i-2001-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
6. Lower the vehicle.
7. Install the reusable strap in order to secure the coolant heater cord to the diagonal brace.

1. Remove the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) Engine Controls - 3.6L (LY7).
2. Remove the coolant (block) heater cord from the transmission fill tube.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Remove the catalytic converter. Refer to «Catalytic Converter Replacement»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
5. Remove the engine coolant (block) heater cord from the engine coolant heater.
6. Remove the engine coolant (block) heater cord.

1. Install the engine coolant (block) heater cord above the transmission.
2. Install the engine coolant (block) heater cord to the engine coolant heater.
3. Install the catalytic converter. Refer to «Catalytic Converter Replacement»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
4. Lower the vehicle.
5. Install the coolant (block) heater cord to the transmission fill tube.
6. Install the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) Engine Controls - 3.6L (LY7).

Cooling Fan Control

The engine cooling fan system is controlled by the body control module (BCM) and the powertrain control module (PCM) or engine control module (ECM). The BCM performs the calculations as to how long, when and what speed the cooling fans should turn on. The BCM then sends a class 2 message to the PCM/ECM to engage the cooling fan relays. If there is a malfunction with the BCM, the PCM/ECM will control the engine cooling fans independently. The engine cooling system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the PCM/ECM to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood accessory wiring junction block. The ground path is provided at G100.

During low speed operation, the PCM/ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the cool fan 1 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 2 relay and the right cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the PCM/ECM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM/ECM supplies a ground path for the cooling fan 3 or S/P relay and the cooling fan 2 relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 2 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan 2 relay coil is energized closing the relay contacts and provides battery positive voltage from the cool fan 2 fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.

The BCM and PCM/ECM command Low Speed Fans on under the following conditions

1. Engine coolant temperature exceeds approximately 106°C (223°F).
2. A/C refrigerant pressure exceeds 1 310 kPa (190 psi).
3. After the vehicle is shut off if the engine coolant temperature at key-off is greater than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.

The BCM and PCM/ECM command High Speed Fans on under the following conditions

1. Engine coolant temperature reaches 110°C (230°F).
2. A/C refrigerant pressure exceeds 1 655 kPa (240 psi).
3. When certain DTCs set.

Hot Coolant Temp

The instrument panel cluster (IPC) illuminates the hot coolant temp indicator in the message center when the PCM determines that the coolant temperature is greater than 128°C (262°F). The IPC receives a class 2 message from the PCM requesting illumination.

The IPC sends a class 2 message to the radio in order to activate an audible warning.

Reduced Engine Power

The IPC displays REDUCED ENGINE POWER message when the IPC detects a reduced engine power condition from the PCM. The IPC receives a class 2 message from the PCM requesting illumination when the engine temperature reaches 110°C (230°F).

Coolant Heater

The optional engine coolant heater (RPO K05) is rated at 400 watts and supplies 1365 btu/hr. The engine coolant heater 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 is provided to protect the plug when not in use.

The cooling system's function is to maintain an efficient engine operating temperature during all engine speeds and operating conditions. The cooling system is designed to remove approximately one-third of the heat produced by the burning of the air-fuel mixture. When the engine is cold, the system cools slowly or not at all. This allows the engine to warm quickly.

Cooling Cycle

Coolant is drawn from the radiator outlet and into the water pump inlet by the water pump. Coolant will then be 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, where the radiator absorbs heat.

Some coolant is also pumped from the water pump to the heater core, then back to the water pump. This provides the passenger compartment with heat and defrost.

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, where the radiator absorbs additional heat.

Coolant is also directed to the throttle body, where 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 thermostat. The flow of coolant will either be stopped at the thermostat until the engine is warmed, or the coolant will flow through the thermostat and into the radiator where the radiator is cooled and the coolant cycle is completed.

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.

When the coolant temperature is below 91°C (195°F), 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 91°C (195°F), 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.

Radiator

The radiator is a heat exchanger. It consists of a core and two tanks. The aluminum core is a crossflow tube and fin design. This is a series of tubes that extend side to side from the inlet tank to the outlet tank. Fins are placed around the outside of the tubes to improve heat transfer from the coolant to the atmosphere. The inlet and outlet tanks are molded with a high temperature, nylon reinforced plastic. A high temperature rubber gasket seals the tank flange edge. 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 left hand tank. The drain cock includes the drain cock and drain cock seal.

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

During vehicle use, the coolant 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. Coolant without bubbles absorbs heat much better than coolant with bubbles.

Pressure Cap

The pressure cap is a cap that seals and pressurizes the cooling system. It contains a blow off or pressure valve and a vacuum or atmospheric valve. The pressure valve is held against the seat by a spring of predetermined strength, which protects the radiator by relieving pressure if it exceeds 15 psi. The vacuum valve is held against the seat by a spring, which permits opening of the valve to relieve vacuum created in the cooling system as the radiator cools off. The vacuum, if not relieved, might cause the radiator to collapse.

The pressure cap allows pressure in the cooling system to build up. As the pressure builds, the boiling point of the coolant goes up as well. Therefore, the coolant can be safely run at a temperature much higher than the boiling point of the coolant at atmospheric pressure. The hotter the coolant is, the faster the heat moves from the radiator to the cooler, passing air. The pressure in the cooling system can get too high, however. When the pressure exceeds the strength of the spring, the pressure valve rises so that the excess pressure can escape. As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum causes the vacuum valve to open, allowing outside air into the cooling system. This equalizes the pressure in the cooling system with atmospheric pressure, preventing the radiator from collapsing.

Coolant Recovery System

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

In effect, a cooling system with a coolant recovery reservoir is a closed system. When the pressure in the cooling system gets too high, the pressure valve opens in the pressure cap. This allows the coolant, which has expanded due to being heated, is allowed to flow through the overflow tube and into the recovery reservoir. As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum opens the vacuum valve in the pressure cap, allowing some of the coolant in the reservoir to be siphoned back into the radiator. Under normal operating conditions, coolant is not lost. Although the coolant level in the recovery reservoir goes up and down, the radiator and cooling system are kept full. An advantage to using a coolant recovery reservoir is that most of the air bubbles are eliminated from the cooling system. 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 to 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.

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

Water Pump

The water pump is a centrifugal vane impeller type pump. The pump consists of a housing with coolant inlet and outlet passages 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. These sealed bearings never need to be lubricated. With a sealed bearing, grease cannot leak out, and dirt and water cannot get in.

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

Thermostat

The thermostat is a coolant flow control component. It's purpose is to 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.

Engine Oil Cooler

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

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

Transmission Oil Cooler

The transmission oil cooler is a heat exchanger. It is located inside the right side end tank of the radiator. The transmission fluid temperature is regulated by the temperature of the engine coolant that surrounds the oil cooler as the transmission fluid passes down through the cooler.

Special Tools

Special Tools Illustration Tool Number/Description J 24460-O1 Cooling System Pressure Tester J 24731 Tempilstick J 26568 Coolant and Battery Fluid Tester J 38185 Hose Clamp Pliers J 39400-A Halogen Leak Detector

Scheme 4

Scheme 5

Scheme 6

Scheme 7

See also:
• Scan Tool Does Not Power Up
• DTC P0125
• Testing for Intermittent Conditions and Poor Connections
• Circuit Testing
• Wiring Repairs
• Connector Repairs
• Powertrain Control Module (PCM) Replacement
• Engine Control Module (ECM) Replacement
• Checking Aftermarket Accessories
• Instrument Panel Cluster (IPC) Replacement
• HVAC Schematics
• HVAC Schematics
• Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement
• Engine Coolant Temperature Gage Inaccurate or Inoperative
• Engine Coolant/Water in Transmission
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Coolant in Combustion Chamber
• Coolant in Engine Oil
• Lower Engine Noise, Regardless of Engine Speed
• Cylinder Leakage Test
• Lifting and Jacking the Vehicle
• Starter Motor Replacement (LA1)
• Capacities - Approximate Fluid
• Air Cleaner Intake Duct Replacement
• Brace Replacement - Front Fender Upper Diagonal - Right
• Transmission Fluid Cooler Line Quick Connect Fitting
• Fastener Notice
• Exhaust Crossover Pipe Replacement (LA1)
• Remote Power Steering Fluid Reservoir Replacement (LY7)
• Drive Belt Replacement
• Refrigerant Recovery and Recharging
• Transmission Fluid Checking Procedure
• Tire and Wheel Removal and Installation
• Diagnostic System Check - Engine Cooling
• Symptoms - Engine Cooling
• Diagnostic Trouble Code (DTC) List
• Cooling System Connector End Views
• Engine Overheating
• Engine Coolant Temperature Indicator Always On
• Cooling Fan Always On
• Cooling Fan Inoperative
• Coolant Heater Inoperative
• Loss of Coolant
• Engine Fails To Reach Normal Operating Temperature
• Radiator Replacement (LA1)
• Radiator Replacement (LY7)