Engine Cooling System Buick Park Avenue II рестайлинг

Fastener Tightening Specifications

Fastener Tightening Specifications

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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 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.

Test Description

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

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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 DTCs 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.

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Scan Tool Data Definitions

Commanded Fan 1 / Commanded Fan 2: Scan tool displays ON or OFF. Represents the powertrain control module (PCM) commanded state of the fan 1 (low Speed) and fan 2 (high speed) control circuits.

Coolant Hot Lamp: The scan tool displays ON/OFF. The scan tool displays ON when the engine coolant is above 151°C (260°F).

Coolant Temperature: The scan tool displays -40°C to +151°C (-40°F to +304°F). This data is the coolant temperature the Instrument Cluster is attempting to display on the coolant temperature gage.

ECT: The scan tool displays -40°C to +151°C (-40°F to +304°F). The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream. The PCM applies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.

FC Relay 1: The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.

FC Relay 2 and 3: The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.

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Circuit Description

The following DTCs are for the cooling fan relay control circuits controlled by the powertrain control module (PCM).

1. DTC P0480-low speed cooling fan relay control circuit
2. DTC P0481-high speed cooling fan relay control circuit

Battery positive voltage is supplied to the COOL FAN 1 relay from the COOL FAN 1 fuse. The PCM controls the low speed cooling fan relay by grounding the low speed cooling fan relay control circuit.

Battery positive voltage is supplied to the COOL FAN 2 relay and the COOL FAN series/parallel (S/P) relay coil side from the COOL FAN 1 fuse. Battery positive voltage is supplied to the COOL FAN 2 relay switch side from the COOL FAN 2 fuse. The PCM controls the high speed cooling fan relays by grounding the high speed cooling fan relay control circuit.

The PCM grounds the cooling fan relay control circuits through an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line that is monitored by the PCM. When the PCM is commanding a component ON, the voltage potential of the control circuit should be low, near 0 volts. When the PCM is commanding the control circuit to a component OFF, 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 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 detects any of the above conditions, the DTC will set and the effected driver will be disabled.

Conditions for Running the DTC

1. The ignition is ON.
2. The system voltage is between 9.0-18.0 volts.

Conditions for Setting the DTC

1. An improper voltage level has been detected on the cooling fan relay control circuit.
2. The condition is present for at least 30 seconds.

Action Taken When the DTC Sets

1. The PCM 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 will store the conditions that were present when the DTC set as Freeze Frame and Failure Records data.
3. A history DTC is stored.

Conditions for Clearing the MIL/DTC

1. The PCM 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 AND POOR CONNECTIONS 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 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 S/P and the cooling fan 2 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.
4. 5. Verifies that the PCM is providing ground to the cooling fan 1 relay.
5. 6. Tests for voltage at the coil side of the cooling fan S/P relay. The cool fan 1 fuse supplies battery positive voltage to the coil side of the cooling fan S/P and cooling fan 2 relays.
6. 7. Verifies that the PCM is providing ground to the cooling fan S/P relay.
7. 8. Verifies that the PCM is providing ground to the cooling fan 2 relay.
8. 9. Tests if ground is constantly being applied to the cooling fan relays.
9. 10. Test the control circuit of the cooling fan relays for a short to voltage or an open.
10. 11. Test the control circuit of the cooling fan relays for a short to ground.
11. 12. Test the battery positive voltage circuit for a short to ground.

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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 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 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/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system)
2. «COOLING FAN ALWAYS ON»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system)
3. «COOLING FAN INOPERATIVE»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system)
4. «ENGINE OVERHEATING»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system)
5. «LOSS OF COOLANT»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system)
6. «THERMOSTAT DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis)
7. «COOLANT HEATER INOPERATIVE»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system)
8. «ENGINE FAILS TO REACH NORMAL OPERATING TEMPERATURE»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system)

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Thermostat Diagnosis

Tools Required

J 24731 Tempilstick

Thermostat Test

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 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. J 24731 -206 tempilstick 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. Refer to «THERMOSTAT REPLACEMENT»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-replacement) .

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Pressure Cap Testing

Tools Required

J 24460-01 Cooling System Pressure Tester

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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.
4. Test the pressure cap for the following conditions: Pressure release when the J 24460-01 exceeds the pressure rating of the pressure cap. Maintain the rated pressure for at least 10 seconds.
5. Replace the pressure cap under the following conditions

1. The pressure cap does not release pressure which exceeds the rated pressure of the cap.
2. The pressure cap does not hold the rated pressure.

Cooling System Leak Testing

Tools Required

J 24460-01 Cooling System Pressure Tester

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1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «PRESSURE CAP TESTING»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__pressure-cap-testing) .
3. Use the J 24460-01 in order to apply pressure to the cooling system. Do not exceed the pressure cap rating.
4. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gage for any pressure loss.
5. Repair any leaks as required.

Draining Procedure

Tools Required

J 26568 Coolant and Battery Tester

Note. If the procedure below is not followed a low or high coolant level condition and/or vehicle damage could result.

1. Raise and support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/buick/park-avenue/ii-2002-2005/remont/hoistjack/#jacking-and-lifting) .
2. Place a drain pan under the drain cock.
3. Open the radiator drain cock.
4. Drain the cooling system.
5. Remove the coolant pressure cap.
6. If a complete engine block drain is required, remove the engine block drain plug.
7. Inspect the coolant.
8. Follow the appropriate procedure based on the condition of the coolant.

1. Normal in appearance-follow the filling procedure.
2. Discolored-follow the flush procedure. Refer to «FLUSHING»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .

Filling Procedure

Note. Refer to FASTENER NOTICE .

1. Close the radiator drain cock. Tighten Tighten the radiator drain cock to 2 N.m (18 lb in).
2. If the engine block drain plug was removed, perform the following: Apply pipe sealer to the drain plug. Install the drain plug. Tighten Tighten the drain plug to 22 N.m (16 lb ft).
3. Lower the vehicle.
4. Open the cooling system bleeder screws. IMPORTANT: Use a 50/50 mixture of DEX-COOL antifreeze and clean, drinkable water.
5. Slowly fill the cooling system with a 50/50 coolant mixture. Refer to MAINTENANCE.
6. Close the cooling system bleeder screws.
7. Install the coolant pressure cap.
8. Start the engine.
9. Run the engine at 2000 - 2500 RPM until the engine reaches normal operating temperature.
10. Allow the engine to idle for 3 minutes.
11. Shut the engine off.
12. Allow the engine to cool.
13. Top off the coolant as necessary.
14. Inspect the concentration of the engine coolant. Using the J 26568 .
15. 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/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the coolant recovery reservoir. Refer to «COOLANT RECOVERY RESERVOIR REPLACEMENT»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__coolant-recovery-reservoir-replacement) .
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/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__coolant-recovery-reservoir-replacement) .
5. Follow the drain and fill procedure using only clean, drinkable water. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#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/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#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/park-avenue/ii-2002-2005/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.

Coolant Recovery Reservoir Replacement

Tools Required

J 38185 Hose Clamp Pliers

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1. Drain the coolant. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Disconnect the air cleaner assembly and position out of the way.
3. Remove the coolant reservoir nuts and bolts.
4. Remove the coolant hose using the J 38185 .
5. Remove the coolant reservoir from the vehicle.

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1. Install the coolant hose to the reservoir using the J 38185 .
2. Install the coolant reservoir. NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
3. Install the coolant reservoir mounting nuts and bolts. Tighten Tighten the coolant reservoir mounting bolt to 9 N.m (80 lb in). Tighten the coolant reservoir mounting nuts to 6 N.m (53 lb in).
4. Reposition the air cleaner.
5. Refill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .

Radiator Hose Replacement-Inlet

Tools Required

J 38185 Hose Clamp Pliers

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1. Drain the engine coolant. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using the J 38185 loosen and move the inlet radiator hose clamp at the radiator.
3. Remove the inlet radiator hose from the radiator.
4. Using the J 38185 loosen and move the inlet radiator hose clamp at the engine.
5. Remove the inlet radiator hose from the engine.

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1. Install the inlet radiator hose to the engine.
2. Install the inlet radiator hose to the radiator.
3. Using the J 38185 install the inlet radiator hose clamps.
4. Fill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .

Radiator Hose Replacement-Outlet

Tools Required

J 38185 Hose Clamp Pliers

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1. Drain the engine coolant. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using the J 38185 loosen and move the outlet radiator hose clamp at the radiator.
3. Remove the outlet radiator hose from the radiator.
4. Using the J 38185 loosen and move the outlet radiator hose clamp at the engine.
5. Remove the outlet radiator hose from the engine.

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1. Install the outlet radiator hose to the engine.
2. Install the outlet radiator hose to the radiator.
3. Using the J 38185 install the outlet radiator hose clamps.
4. Fill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .

Cooling Fan Replacement-Electric

Tools Required

J 41623-B Cooler Quick Connect Tool

Removal Procedure

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1. Drain the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner assembly.
3. Remove the front headlamps. Refer to HEADLAMP REPLACEMENT in Lighting Systems.
4. Remove the upper radiator seal.
5. Remove the battery cable to transmission oil cooler line clip and position the cable aside.
6. Remove the oil fill cap from the sight shield.
7. Remove the engine oil dipstick.
8. Disconnect the upper transmission oil cooler line using the J 41623-B .
9. Disconnect the upper radiator hose from the radiator.
10. Disconnect the wiring harness electrical connectors from the cooling fan motors.
11. Remove the cooing fan mounting bolts from the radiator.
12. Remove the coolant overflow hose from the fan assembly.
13. Remove the fans by releasing from the lower mounting tabs and raise the left side of the fans up.

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1. Install the fan assembly and insert into the lower radiator holding tabs. NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
2. Install the electric cooling fan mounting bolts Tighten Tighten the electric cooling fan mounting bolts to 9 N.m (80 lb in).
3. Install the coolant overflow hose into the fan shroud clips.
4. Connect the wiring harness electrical connectors to the fan motors.
5. Install the upper radiator hose to the radiator.
6. Connect the upper transmission oil cooler line.
7. Install the engine oil dipstick.
8. Install the oil fill cap to the sight shield.
9. Install the battery cable to transmission oil cooler line clip and reposition the cable.
10. Install the upper radiator seal.
11. Install the front headlamps. Refer to HEADLAMP REPLACEMENT in Lighting Systems.
12. Fill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .

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1. Remove the electric cooling fan. Refer to «COOLING FAN REPLACEMENT-ELECTRIC»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-replacement-electric) . IMPORTANT: The fan blade retaining nut is left hand thread.
2. Remove the fan blade retaining nut (5) from the electric cooling fan motors (2).
3. Remove the fan blade (4) from the motor shaft.
4. Remove the cooling fan motor retaining screws (3).
5. Remove the cooling fan motor (2) from the shroud (1).

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1. Install the cooling fan motor (2) to the shroud (1). NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
2. Install the cooling fan motor retaining bolts (3). Tighten Tighten the bolts to 6 N.m (53 lb in).
3. Install the cooling fan blade (4) to the motor shaft. IMPORTANT: The fan blade retaining nut is left hand thread.
4. Install the cooling fan retaining nut (5) to the motors (2). Tighten Tighten the nut to 6 N.m (53 lb in).
5. Install the electric cooling fan. Refer to «COOLING FAN REPLACEMENT-ELECTRIC»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-replacement-electric) .

Thermostat Replacement

Tools Required

J 38185 Hose Clamp Pliers

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1. Remove the engine cover. Refer to FUEL INJECTOR SIGHT SHIELD REPLACEMENT (L36) or FUEL INJECTOR SIGHT SHIELD REPLACEMENT (L67) in Engine Mechanical.
2. Drain the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Using the J 38185 loosen and move the inlet radiator hose clamp at the thermostat housing.
4. Remove the inlet hose from the housing.
5. Remove the thermostat housing bolts (1).
6. Remove the thermostat housing (2).
7. Remove the thermostat (4).
8. Clean the gasket mating surfaces and the housing and intake port.

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1. Install the thermostat (4).
2. Install the thermostat housing (2) and a new gasket (3). NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
3. Install the thermostat housing bolts (1). Tighten Tighten the thermostat housing bolts to 20 N.m (15 lb ft).
4. Install the inlet radiator hose and clamp.
5. Refill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Install the engine cover. Refer to FUEL INJECTOR SIGHT SHIELD REPLACEMENT (L36) or FUEL INJECTOR SIGHT SHIELD REPLACEMENT (L67) in Engine Mechanical.

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1. Drain the engine coolant. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the drive belt. Refer to DRIVE BELT REPLACEMENT (L36) or DRIVE BELT REPLACEMENT (L67) in Engine Mechanical-3.8L.
3. Remove the water pump pulley bolts.
4. Remove the water pump pulley.
5. Remove the water pump mounting bolts (1, 2).
6. Remove the water pump.
7. Clean the gasket mating surfaces.
8. Clean and inspect the water pump. Refer to WATER PUMP CLEANING AND INSPECTION in Engine Mechanical-3.8L Unit Repair.

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1. Using a new gasket, install the water pump on the engine. NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
2. Install the water pump mounting bolts (1, 2). Tighten Tighten the short bolts (1) to 15 N.m (11 lb ft). Tighten the long bolts (2) to 30 N.m (22 lb ft).
3. Install the water pump pulley and bolts. Tighten Tighten the water pump pulley bolts to 13 N.m (115 lb in).
4. Install the drive belt. Refer to DRIVE BELT REPLACEMENT (L36) or DRIVE BELT REPLACEMENT (L67) in Engine Mechanical-3.8L.
5. Fill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .

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1. Drain the engine coolant. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the drive belt. Refer to DRIVE BELT REPLACEMENT (L36) or DRIVE BELT REPLACEMENT (L67) in Engine Mechanical-3.8L.
3. Remove the supercharger idler pulley assembly. Refer to DRIVE BELT IDLER PULLEY BRACKET REPLACEMENT (L67) in Engine Mechanical-3.8L.
4. Remove the water pump pulley bolts.
5. Remove the water pump pulley.
6. Remove the water pump mounting bolts (1, 2).
7. Remove the water pump.
8. Clean the gasket mating surfaces.

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1. Using a new gasket, install the water pump on the engine. NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
2. Install the water pump mounting bolts (1, 2). Tighten Tighten the short bolts (1) to 15 N.m (11 lb ft). Tighten the long bolts (2) to 30 N.m (22 lb ft).
3. Install the water pump pulley and bolts. Tighten Tighten the water pump pulley bolts to 13 N.m (115 lb in).
4. Install the supercharger idler pulley assembly. Refer to DRIVE BELT IDLER PULLEY BRACKET REPLACEMENT (L67) in Engine Mechanical-3.8L.
5. Install the drive belt. Refer to DRIVE BELT REPLACEMENT (L36) or DRIVE BELT REPLACEMENT (L67) in Engine Mechanical-3.8L.
6. Fill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .

Radiator Replacement

Tools Required

1. J 41623-B Cooler Quick Connect Tool
2. J 38185 Hose Clamp Pliers

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1. Remove the cooling fans. Refer to «COOLING FAN REPLACEMENT-ELECTRIC»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-replacement-electric) .
2. Remove the hood latch support. Refer to HOOD LATCH SUPPORT REPLACEMENT in Body Front End.
3. Remove the upper radiator seal.
4. Remove the upper radiator hose from the radiator using the J 38185 .
5. Remove the lower radiator hose from the radiator using the J 38185 .
6. Slide the plastic cap off the transaxle oil cooler pipe quick connect fittings.
7. Using the J 41623-B disconnect the upper transmission oil cooler line (1).
8. Using the J 41623-B disconnect the lower transmission oil cooler line (2).
9. Remove the overflow hose from the radiator.
10. Remove the condenser to radiator mounting screws.
11. Remove the upper radiator mounting bracket retaining bolts and brackets.
12. Remove the radiator from the vehicle.

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1. Install the radiator to the vehicle
2. Install the upper radiator mounting brackets. NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
3. Install the upper radiator mounting brackets retaining bolts. Tighten Tighten the bolts to 10 N.m (89 lb in). NOTE: The bolt retaining the condenser to the radiator end tank is a special length and should be the ONLY bolt used upon reinstallation. The use of a longer bolt will damage the radiator end tank.
4. Install the condenser mounting bolts. Tighten Tighten the bolts to 13 N.m (10 lb ft).
5. Install the overflow hose to the radiator.
6. Connect the lower transmission oil cooler line (1).
7. Connect the upper transmission oil cooler line (2).
8. Slide the plastic cap over the transaxle oil cooler pipe quick connect fittings.
9. Install the lower radiator hose to the radiator using the J 38185 .
10. Install the upper radiator hose to the radiator using the J 38185 .
11. Install the upper radiator seal.
12. Install the hood latch support. Refer to HOOD LATCH SUPPORT REPLACEMENT in Body Front End.
13. Install the cooling fans. Refer to «COOLING FAN REPLACEMENT-ELECTRIC»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-replacement-electric) .
14. Inspect the transmission oil level. Refer to «CHECKING FLUID LEVEL & CONDITION»(/buick/park-avenue/ii-2002-2005/remont/automatic-trans/#automatic-transmission-servicing__checking-fluid-level-condition) .

Scheme 71

1. Drain the engine coolant. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Raise and support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/buick/park-avenue/ii-2002-2005/remont/hoistjack/#jacking-and-lifting) .
3. Remove the lower radiator air deflector. Refer to AIR DEFLECTOR REPLACEMENT - FRONT in Body Front End.
4. Disconnect the coolant heater cord (2) from the coolant heater (1).
5. Loosen the bolt at the coolant heater, but do not remove.
6. Remove the coolant heater.
7. Remove and clean any burrs, compound, paint, or rough spots from the core plug hole.

Scheme 72

Scheme 73

1. Apply a coat of Permatex® Thread Sealant with Teflon to the O-ring. IMPORTANT: Ensure both locking wings (1) are positioned against the inner wall of the engine block.
2. Install the coolant heater by pushing tight to the block.
3. Install the coolant heater so the element (1) is positioned at approximately the 3 o'clock position. NOTE: Refer to «FASTENER NOTICE»(/buick/park-avenue/ii-2002-2005/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) .
4. Tighten the bolt until both locking wings draw tight against the inner wall of the engine block. Tighten Tighten the coolant heater bolt to 2 N.m (18 lb in).
5. Install the coolant heater cord (2) to the coolant heater.
6. Fill the cooling system. Refer to «DRAINING AND FILLING COOLING SYSTEM»(/buick/park-avenue/ii-2002-2005/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Install the lower radiator air deflector. Refer to AIR DEFLECTOR REPLACEMENT - FRONT in Body Front End.

Scheme 74

1. Disconnect the coolant heater cord (3) from the coolant heater (2).
2. Cut the coolant heater cord straps (1) from the positive battery cable conduit.
3. Remove the coolant heater cord (3) from the vehicle.

Scheme 75

1. Install the coolant heater cord (3) to the vehicle.
2. Connect the coolant heater cord (3) to the coolant heater (2).
3. Route the coolant heater cord (3) along the positive battery cable conduit. IMPORTANT: Ensure all slack is removed from the coolant heater cord (3) prior to tightening the coolant heater cord straps (1).
4. Tie new coolant heater cord straps (1) to the positive battery cable conduit.
5. Secure the excess coolant heater cord (3) to the negative battery cable conduit, behind the tie bar.

Cooling Fan Control

The engine cooling fan system consists of two electrical cooling fans and three fan relays. The relays are arranged in a series/parallel configuration that allows the powertrain control module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage on two individual circuits, from the left underhood fuse block and the right underhood fuse block. The ground path is provided at G105.

During low speed operation, the PCM 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 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 PCM 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 supplies a ground path for the cooling fan 2 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 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 PCM commands Low Speed Fans on under the following conditions

1. Engine coolant temperature exceeds approximately 100°C (212°F).
2. When A/C is requested and the ambient temperature is greater than 4°C (39°F).
3. A/C refrigerant pressure exceeds 1310 kPa (190 psi).
4. 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 PCM commands High Speed Fans on under the following conditions

1. Engine coolant temperature reaches 108°C (226°F).
2. A/C refrigerant pressure exceeds 1682 kPa (244 psi).
3. When certain DTCs set.

Engine Coolant Indicator(s)

The IPC illuminates the hot coolant temperature indicator when the IPC determines that the coolant temperature is greater than 124°C (255°F). The IPC receives a class 2 message from the PCM indicating the coolant temperature. The IPC sends a class 2 message to the BCM in order to activate an audible warning.

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 on the cord is provided to protect the plug when not in use.

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 it 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.

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 it 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 it absorbs additional heat.

Coolant is also directed to the throttle body. There it 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 it will flow through the thermostat and into the radiator where it 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.

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 its 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 its seat by a spring, which permits opening of the valve to relieve vacuum created in the cooling system as it cools off. The vacuum, if not relieved, might cause the radiator 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, it raises the pressure valve 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. It is partially filled with coolant and is connected to the radiator fill neck with the overflow tube. Coolant can flow back and forth between the radiator and the reservoir.

In effect, a cooling system with a coolant recovery reservoir is a closed system. When the pressure in the cooling system gets too high, it will open the pressure valve in the pressure cap. This allows the coolant, which has expanded due to being heated, 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, no coolant is lost. Although the coolant level in the recovery reservoir goes up and down, the radiator and cooling system are kept full. An advantage to using a coolant recovery reservoir is that it eliminates almost all air bubbles from the cooling system. Coolant without 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.

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.

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 n 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.

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.

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.

Scheme 76

See also:
• LIFTING AND JACKING THE VEHICLE
• FASTENER NOTICE
• CHECKING FLUID LEVEL & CONDITION
• DIAGNOSTIC SYSTEM CHECK-ENGINE COOLING
• THERMOSTAT DIAGNOSIS
• THERMOSTAT REPLACEMENT
• PRESSURE CAP TESTING
• COOLANT RECOVERY RESERVOIR REPLACEMENT
• COOLING FAN REPLACEMENT-ELECTRIC