Engine Cooling System Buick LaCrosse I

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 1

Scheme 2

Cooling System Connector End Views

Cooling Fan - Left Connector Part Information OEM: Assembly 12033769 Connector 12020341 Connector Seal 12077383 Cable Seal 12040972 Service: 12101917 2-Way F Metri-Pack 630 Series, Sealed, Pull To Seat (BK) Pin Wire Color Circuit No. Function A GY 532 Cooling Fan Motor Supply Voltage B WH 504 Cooling Fan Motor Low Reference

Cooling Fan - Right Connector Part Information OEM: Assembly 12033769 Connector 12020341 Connector Seal 12077383 Cable Seal 12040972 Service: 12101917 2-Way F Metri-Pack 630 Series, Sealed, Pull To Seat (BK) Pin Wire Color Circuit No. Function A BK 250 Ground B L-BU 409 Cooling Fan Motor Supply Voltage

DIAGNOSTIC CODE INDEX

DIAGNOSTIC TROUBLE CODE INDEX

Diagnostic Starting Point - Engine Cooling

Begin the system diagnosis with the Diagnostic System Check - Vehicle . 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 Class 2 serial data circuit
3. The identification of any stored diagnostic trouble codes (DTCs) and their status

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

Scan Tool Output Controls

Powertrain Control Module (PCM)

Scan Tool Data List

Powertrain Control Module (PCM) 3.8 L

Circuit Description

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

The ECM monitors the relay control circuits for the following conditions

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

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

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

DTC Descriptors

This diagnostic procedure supports the following DTCs

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

Conditions for Running the DTC

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

P0481

The ECM detects an open circuit on the high speed cooling fan relay control circuit.

P0693

The ECM detects a short to ground on the high speed cooling fan relay control circuit.

P0694

The ECM detects a short to voltage on the high speed cooling fan relay control circuit.

The above condition is present for one second.

P0480

The ECM detects an open on the low speed cooling fan relay control circuit.

P0691

The ECM detects a short to ground on the low speed cooling fan relay control circuit.

P0692

The ECM detects a short to voltage on the low speed cooling fan relay control circuit.

Action Taken When DTC Sets

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

Conditions for Clearing MIL/DTC

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

Diagnostic Aids

1. If the condition is not present, refer to «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) in Wiring Systems.
2. Review the Freeze/Failure Records vehicle mileage since the diagnostic test failed. This may help determine how often the condition that caused the DTC to be set occurs.

Test Description

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

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

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

The powertrain control module (PCM) uses the engine coolant temperature (ECT) sensor to monitor the engine for an over temperature condition. When an over temperature condition is present, DTC P1258 will set.

1. A P1258 fault is enabled.
2. The PCM has performed the coolant temperature check.

Conditions for Setting the DTC

The PCM has disabled the fuel injectors.

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/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__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/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__engine-coolant-temperature-indicator-always-on)
2. «Cooling Fan Always On»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-always-on)
3. «Cooling Fan Inoperative»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-inoperative)
4. «Coolant Heater Inoperative»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__coolant-heater-inoperative)
5. «Engine Overheating (LY7)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating-ly7)
6. «Loss of Coolant»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant)
7. «Thermostat Diagnosis (LY7)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system)
8. «Engine Fails To Reach Normal Operating Temperature (LY7)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#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 (LY7)

Engine Overheating (LY7)

Loss of Coolant

Loss of Coolant

Tools Required

J 24731 Tempilstick. See Special Tools .

Test Procedure

Note. The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil-like device which has a wax material containing certain chemicals that 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 outlet coolant pipe.

1. Use a tempilstick in order to find the opening and the closing temperatures of the thermostat. J 24731 188 tempilstick melts at 87°C (188°F). See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . The thermostat should begin to open at 90°C (194°F). J 24731 206 tempilstick melts at 97°C (206°F). See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . The thermostat should be fully open at 107°C (225°F).
2. Replace the thermostat if it does not operate properly between this temperature range.

Coolant Heater Inoperative

Coolant Heater Inoperative

Engine Fails To Reach Normal Operating Temperature (LY7)

Engine Fails To Reach Normal Operating Temperature (LY7)

1. J 24460-01 Cooling System Pressure Tester. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
2. J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the J 24460-01 (1) with J 42401 (2) in order to test the pressure cap. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
4. Test the pressure cap for the following conditions: Pressure release when the J 24460-01 exceeds the pressure rating of the pressure cap. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Maintain the rated pressure for at least 10 seconds. Note the rate of pressure loss.
5. Replace the pressure cap under the following conditions: The pressure cap does not release pressure which exceeds the rated pressure of the cap. The pressure cap does not hold the rated pressure.

1. J 24460-01 Cooling System Pressure Tester. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
2. J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Wash the pressure cap mating surface with water.
4. Use the J 24460-01 (1) with J 42401 (2) in order to apply pressure to the cooling system. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Do not exceed the pressure cap rating.
5. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gage for any pressure loss.
6. Repair any leaks as required.

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

Draining Procedure

1. Remove the coolant pressure cap.
2. Place a drain pan under the drain cock.
3. Open the radiator drain cock.
4. Drain the cooling system.
5. If a complete engine block drain is required, remove the knock sensors. Refer to «Knock Sensor (KS) 1 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) and «Knock Sensor (KS) 2 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) in Engine Controls - 3.8L
6. Inspect the coolant.
7. 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/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

Filling Procedure

1. Close the radiator drain cock.
2. If the engine block was drained, install the knock sensors. Refer to «Knock Sensor (KS) 1 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) and «Knock Sensor (KS) 2 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) in Engine Controls - 3.8L
3. Open the cooling system bleeder screw.
4. Slowly fill the cooling system with a 50/50 coolant mixture. Refer to «Capacities - Approximate Fluid»(/buick/lacrosse/i-2004-2009/remont/lubrication-system/#maintenance-and-lubrication__capacities-approximate-fluid) .
5. After the coolant is visible and stable at the filler neck, push down on the upper radiator hose to remove air. While pushing down on the radiator hose ensure that the filler neck is full of coolant.
6. Close the cooling system bleeder screw.
7. Release the upper radiator hose and add coolant to the filler neck.
8. Push down on the upper radiator hose and try to move any air in the upper hose back to the radiator. Repeat this step three times and add coolant to the filler neck each time.
9. Install the coolant pressure cap.
10. Fill the coolant recovery bottle to the indicator line, then add 400 milliliters (13.5 ounces) more.
11. Start the engine.
12. Run the engine at 2,500 RPM until the engine is hot enough to open the thermostat.
13. Allow the engine to idle for 3 minutes.
14. Shut the engine OFF.
15. Allow the engine to cool.
16. Top off the coolant as necessary.
17. Inspect the concentration of the engine coolant using the J 26568 . See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
18. Rinse away any excess coolant from the engine and the engine compartment.

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

1. Remove the coolant pressure cap.
2. Place a drain pan under the drain cock.
3. Open the radiator drain cock.
4. Drain the cooling system.
5. If a complete engine block drain is required, remove the coolant drain plugs from the engine block. Refer to «Engine Block Disassemble»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-3-of-5__engine-block-disassemble) for the 3.6L (LY7) engine.
6. Inspect the coolant.
7. 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/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

1. Close the radiator drain cock.
2. If a complete engine block drain was required, install the coolant drain plugs to the engine block. Refer to «Engine Block Disassemble»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-3-of-5__engine-block-disassemble) for the 3.6L (LY7) engine.
3. Slowly fill the cooling system with a 50/50 coolant mixture until the coolant level is visible and stable. Refer to «Capacities - Approximate Fluid»(/buick/lacrosse/i-2004-2009/remont/lubrication-system/#maintenance-and-lubrication__capacities-approximate-fluid)
4. Install the pressure cap loosely (threaded on about one turn).
5. Start the engine and raise the engine speed to 2,500 RPM and hold it there for 40 seconds, then shut engine off.
6. Remove the pressure cap and fill the coolant system until the level is visible and stable.
7. Install the pressure cap loosely (threaded on about one turn).
8. Start the engine and raise the engine speed to 2,500 RPM and hold it there for 30 seconds, then shut engine off.
9. Remove the pressure cap and fill the coolant system until the level is visible and stable.
10. Install the pressure cap loosely (threaded on about one turn).
11. Start the engine and raise the engine speed to 2,500 RPM and hold it there for 20 seconds, then shut engine off.
12. Remove the pressure cap and fill the coolant system until the level is visible and stable.
13. Install the pressure cap, fully threaded on.
14. Fill the coolant recovery bottle to the indicator line, then add 400 milliliters (13.5 ounces) more.
15. Start the engine and run it above 2500 RPM until it is hot enough to open the thermostat, this will allow the trapped air to be purged from the engine.
16. Complete a series of three, four-second-duration idles with four-second-duration 3000 RPM cycles.
17. Turn the engine off and allow it to cool down.
18. Fill the coolant recovery bottle to the indicator line.
19. Inspect the concentration of the engine coolant using the J 26568 . See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
20. Rinse away any excess coolant from the engine and the engine compartment.

1. J 26568 Coolant and Battery Fluid Tester. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
2. J 42401 Radiator Cap and Surge Tank Test Adapter. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
3. GE-47716 Vac-N-Fill Coolant Refill Tool. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .

1. Remove the coolant pressure cap.
2. Place a drain pan under the drain cock.
3. Open the radiator drain cock.
4. Drain the cooling system.
5. If a complete engine block drain is required, remove the knock sensors for the 3.8L engine or the engine block drain plugs for the 3.6L engine. Refer to «Knock Sensor (KS) 1 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) and «Knock Sensor (KS) 2 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) for the 3.8L engine or to «Engine Block Disassemble»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-3-of-5__engine-block-disassemble) for the 3.6L (LY7) engine.
6. Inspect the coolant.
7. 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/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

Vac-N-Fill Procedure

1. If a complete engine block drain was required, install the knock sensors for the 3.8L engine or the engine block drain plugs for the 3.6L engine. Refer to «Knock Sensor (KS) 1 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) and «Knock Sensor (KS) 2 Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) for the 3.8L engine or to «Engine Block Disassemble»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-3-of-5__engine-block-disassemble) for the 3.6L (LY7) engine.
2. Install the J 42401 to the coolant fill port. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Attach the Vac-N-Fill cap to the J 42401 Radiator Cap and Surge Tank Test Adapter. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
3. Attach the vacuum gauge assembly to the Vac-N-Fill cap.
4. Attach the fill hose to the barb fitting on the vacuum gage assembly. Ensure that the valve is closed.
5. Pour the coolant mixture into the graduated reservoir.
6. Place the fill hose in the graduated reservoir.
7. Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.
8. Attach the venturi assembly to the vacuum tank.
9. Attach a shop air hose to the venturi assembly. Ensure the valve on the venturi assembly is closed.
10. Attach the vacuum hose to the vacuum gage assembly and the vacuum tank.
11. Open the valve on the venturi assembly. The vacuum gage will begin to rise and a hissing noise will be present.
12. Continue to draw vacuum until the needle stops rising. This should be 610-660 mm Hg (24-26 in Hg). Cooling hoses may start to collapse. This is normal due to vacuum draw.
13. To aid in the fill process, position the graduated reservoir above the coolant fill port.
14. Slowly open the valve on the vacuum gage assembly. When the coolant reaches the top of the fill hose, close the valve. This will eliminate air from the fill hose.
15. Close the valve on the venturi assembly.
16. If there is a suspected leak in the cooling system, allow the system to stabilize under vacuum and monitor for vacuum loss. If vacuum loss is observed. Refer to «Loss of Coolant»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
17. Open the valve on the vacuum gage assembly. The vacuum gage will drop as coolant is drawn into the system.
18. Once the vacuum gage reaches zero, close the valve on the vacuum gage assembly and repeat steps 11-17.
19. Detach the Vac-N-Fill cap from the J 42401 . See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
20. Remove the J 42401 from the coolant fill port. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
21. Add coolant to the system as necessary.
22. Inspect the concentration of the coolant mixture using the J 26568 . See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
23. Detach the vacuum hose from the vacuum gage assembly.
24. Attach the extraction hose to the vacuum hose.
25. Open the valve on the venturi assembly to start a vacuum draw.
26. Use the extraction hose to draw out coolant to the proper level.
27. The vacuum tank has a drain valve on the bottom of the tank. Open the valve to drain coolant from the vacuum tank into a suitable container for disposal.
28. Fill the coolant recovery bottle to the indicator line, then add 400 milliliters (13.5 ounces) more.
29. Start the engine and run it above 2500 RPM until it is hot enough to open the thermostat.
30. Complete a series of three, four-second-duration idles with four-second-duration 3000 RPM cycles.
31. Turn the engine off and allow it to cool down to room temperature.
32. Fill the coolant recovery bottle to the indicator line.

Flushing

Store used coolant in a properly labeled container. 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.

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 (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#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/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Follow the drain and fill procedure using only clean, drinkable water. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/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 (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/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 (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/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.

Removal Procedure

1. Reposition the coolant reservoir hose clamp (1) aside at the radiator overflow fitting.
2. Remove the coolant reservoir hose from the radiator overflow fitting.
3. Disconnect the coolant reservoir hose support retainer from the electrical harness.
4. Remove the coolant reservoir nuts (2) from the shock tower studs.
5. Remove the coolant recovery reservoir (3) from the lower retainer and the shock tower studs.
6. Drain the coolant from the recovery reservoir into a clean container.

Installation Procedure

1. Install the coolant recovery reservoir (3) to the lower retainer and the shock tower studs.
2. Install the nuts (2) to the shock tower studs. Tighten: Tighten the nuts to 3.3 N.m (29 In. Lbs.).
3. Lubricate the reservoir hose with clean water. Route the hose to the radiator overflow neck fitting.
4. Install the coolant reservoir hose (1) to the radiator overflow fitting.
5. Connect the coolant reservoir hose support retainer to the electrical harness.
6. Position the coolant reservoir hose clamp to the radiator overflow fitting.
7. Fill the coolant recovery reservoir to the proper level.

J 38185 Hose Clamp Pliers. See Special Tools .

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the left diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal»(/buick/lacrosse/i-2004-2009/remont/exterior-body-panels/#body-front-end) in Body Front End.
3. Use the J 38185 in order to reposition the hose clamp from the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
4. Remove the radiator inlet hose from the radiator.
5. Use the J 38185 in order to reposition the hose clamp from the water outlet housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
6. Remove the radiator inlet hose from the water outlet housing and the vehicle.

1. Align the marks on the hose. Install the radiator inlet hose to the water outlet housing.
2. Use the J 38185 in order to reposition and install the hose clamp to the water outlet housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
3. Install the radiator inlet hose to the radiator.
4. Use the J 38185 in order to reposition and install the hose clamp to the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
5. Install the left diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal»(/buick/lacrosse/i-2004-2009/remont/exterior-body-panels/#body-front-end) in Body Front End.
6. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 3

Radiator Hose Replacement - Inlet (3.6L)

J 38185 Hose Clamp Pliers. See Special Tools .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the lower radiator air deflector. Refer to «Radiator Air Baffle and Deflector Replacement - Lower»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Use the J 38185 in order to reposition the hose clamp from the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
4. Remove the radiator outlet hose (3) from the radiator (2).
5. Lower the vehicle.
6. Use J 38185 in order to reposition the hose clamp from the water pump housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
7. Remove the radiator outlet hose from the water pump housing.

1. Align the marks on the hose. Install the radiator outlet hose to the water pump housing.
2. Use J 38185 in order to reposition the hose clamp to the water pump housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Install the radiator outlet hose (3) to the radiator (2).
5. Use J 38185 in order to reposition the hose clamp to the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
6. Install the lower radiator air deflector. Refer to «Radiator Air Baffle and Deflector Replacement - Lower»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 4

Radiator Hose Replacement - Outlet (3.6L)

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Disconnect the following from the remote power steering fluid reservoir (1): The brake booster hose The wiring harness (2)
3. Remove the remote power steering fluid reservoir mounting bolts (1, 3) ONLY, and position aside.
4. Remove the wiper motor module in order to gain access to the rear of the throttle body heater inlet hose. Refer to «Wiper Motor, Wiper System Module Replacement»(/buick/lacrosse/i-2004-2009/remont/wiperwasher-systems/#wiper-system-washer-system) in Wipers/Washer Systems.
5. Disconnect the heated oxygen sensor connector (2) from the rear of the throttle body heater inlet hose/pipe (3).
6. Disconnect the throttle body heater inlet hose from the water crossover, using 90 degrees needle-nose pliers.
7. Disconnect the electrical connector (2) from the coil pack (1).
8. Disconnect the following from the front of the throttle body heater inlet hose/pipe: The camshaft position (CMP) sensor connector The left knock sensor connector The vacuum pipe retainer
9. Disconnect the vacuum brake booster hose (3) from the vacuum source.
10. Remove the bolts securing the throttle body heater inlet hose/pipe to the following: The intake plenum (2) The engine rear lift bracket
11. Disconnect the throttle body heater inlet hose from the throttle body.
12. Remove the throttle body heater inlet hose/pipe from the engine.

1. Position the throttle body heater inlet hose/pipe to the engine.
2. Connect the throttle body heater inlet hose to the throttle body.
3. Install the bolts securing the throttle body heater inlet hose/pipe to the following: The intake plenum (2) The engine rear lift bracket Tighten: Tighten the throttle body heater inlet hose/pipe bolts to 9 N.m (80 In. Lbs.).
4. Connect the vacuum brake booster hose (3) to the vacuum source.
5. Connect the following to the front of the throttle body heater inlet hose/pipe: The CMP sensor connector The left knock sensor connector The vacuum pipe retainer
6. Connect the electrical connector (2) to the coil pack (1).
7. Connect the throttle body heater inlet hose to the water crossover, using 90 degrees needle-nose pliers.
8. Connect the heated oxygen sensor connector (2) to the rear of the throttle body heater inlet hose/pipe (3).
9. Install the wiper motor module. Refer to «Wiper Motor, Wiper System Module Replacement»(/buick/lacrosse/i-2004-2009/remont/wiperwasher-systems/#wiper-system-washer-system) in Wipers/Washer Systems.
10. Install the remote power steering fluid reservoir mounting bolts (1, 3). Tighten: Tighten the remote power steering fluid reservoir to intake plenum mounting bolts to 9 N.m (80 In. Lbs.). Tighten the remote power steering fluid reservoir to cylinder head mounting bolt to 25 N.m (18 Ft. Lbs.).
11. Connect the following to the remote power steering fluid reservoir (1): The brake booster hose The wiring harness (2)
12. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

GE-47827 Socket. See Special Tools .

1. Remove the fan shroud assembly from the vehicle. Refer to «Fan Shroud Replacement (L26)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Shroud Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Using GE-47827 turn the fan motor drive plate in the opposite direction of the arrow on the fan blade until the motor drive plate disengages from the fan blade. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
3. Remove and discard the fan blade.
4. Center punch each of the rivets (1) from the rear of the motor.
5. Drill the head of the rivets (1) from the fan motor using a 6.35 mm (0.25 in) drill bit.
6. Tap the rivets out of the fan shroud.
7. Remove the fan motor from the fan shroud.
8. Remove the tape covering the entry points from the fan motor.

1. Install the engine cooling fan motor to the fan shroud.
2. Install the cooling fan motor bolts.
3. Install the cooling fan motor nuts. Tighten: Tighten the nuts to 6 N.m (53 In. Lbs.).
4. Install the new engine cooling fan blade.
5. Using the GE-47827 turn the fan motor drive plate in the same direction of the arrow on the fan blade until the fan motor drive plate engages to the fan blade. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) . Full engagement is attained when the motor drive plate fully occupies the three slots in the face of the fan blade.
6. Rotate the cooling fan blade to ensure proper rotation.
7. Install the fan shroud assembly to the vehicle. Refer to «Fan Shroud Replacement (L26)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Fan Shroud Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the left and right engine mount struts. Refer to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) and to «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
3. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) in Engine Controls - 3.8L.
4. Remove the powertrain control module (PCM) harness retainer from the fan shroud.
5. Remove the transmission oil cooler lines from the lower fan shroud clip and reposition the oil cooler lines aside.
6. Remove the fan shroud clip from the condenser tubes.
7. Remove the radiator upper bracket bolts and brackets.
8. Remove the cooling fan shroud bolts.
9. Remove the bolt that connects the fan shroud to the condenser hold down bracket.
10. Disconnect the engine cooling fan motors electrical connectors.
11. Remove the cooling fan electrical harness from the fan shroud clips.
12. Remove the cooling fan shroud.
13. Remove the engine cooling fan blade nut.
14. Remove the engine cooling fan blade.
15. Inspect the cooling fan blades for the following conditions: Bent or cracked cooling fan blades Smoothness of the cooling fan blade mating surfaces Remove burrs or other imperfections as necessary
16. Remove the engine cooling fan motor bolts.
17. Remove the engine cooling fan motor.

1. Install the engine cooling fan motor.
2. Install the cooling fan motor bolts. Tighten: Tighten the bolts to 6 N.m (53 In. Lbs.).
3. Install the engine cooling fan blade.
4. Install the engine cooling fan blade nut. Tighten: Tighten the nut to 6 N.m (53 In. Lbs.).
5. Install the fan shroud.
6. Install the cooling fan shroud bolts. Tighten: Tighten the bolts to 6 N.m (53 In. Lbs.).
7. Install the cooling fan electrical harness to the fan shroud clips.
8. Connect the engine cooling fan motors electrical connectors.
9. Install the fan shroud clip to the condenser tubes.
10. Install the bolt that connects the fan shroud to the condenser hold down bracket. Tighten: Tighten the bolts to 6 N.m (53 In. Lbs.).
11. Install the radiator upper support brackets and bolts. Tighten: Tighten the bolts to 10 N.m (89 In. Lbs.).
12. Install the transmission oil cooler lines to the retainer at the bottom of the fan shroud.
13. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) in Engine Controls - 3.8L.
14. Install the PCM harness clip on to the fan shroud.
15. Install the engine mount struts. Refer to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) and to «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
16. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
17. Inspect the engine cooling fans for proper operation.

1. Disconnect the heater hoses from the heater core. Refer to «Heater Hoses Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
2. Remove the thermostat. Refer to «Thermostat Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Thermostat Replacement (RPOs L26/L32)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the thermostat housing bolts.
4. Remove the thermostat housing with the heater pipes, hoses and bolts.
5. Carefully clean the sealing surfaces with a plastic gasket scraper such as J 28410 or equivalent.

1. Assemble the heater pipes and hoses to the thermostat housing.
2. Install a new gasket to the thermostat housing.
3. Install the thermostat housing bolts to the thermostat housing. Partially install the thermostat housing bolts in order to retain the gasket.
4. Install the thermostat housing with the heater pipes, heater hoses, gasket and bolts.
5. Install the thermostat housing bolts. Tighten: Tighten the thermostat housing bolts to 20 N.m (15 Ft. Lbs.).
6. Install the thermostat. Refer to «Thermostat Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Thermostat Replacement (RPOs L26/L32)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Connect the heater hoses to the heater core. Refer to «Heater Hoses Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.

J 38185 Hose Clamp Pliers. See Special Tools .

1. Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
2. Partially drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Use the J 38185 in order to reposition the hose clamp from the water outlet housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
4. Remove the radiator inlet hose from the water outlet housing.
5. Reposition the wiring harness from the water outlet housing stud.
6. Remove the water outlet housing bolt and the stud.
7. Remove the water outlet housing and the gasket.
8. Remove the thermostat.
9. Clean and Inspect the water outlet housing gasket mating surfaces.

1. Install the thermostat.
2. Install the gasket and the water outlet housing.
3. Install the water outlet housing bolt and the stud to the water outlet housing. Tighten: Tighten the bolt and the stud to 27 N.m (20 Ft. Lbs.).
4. Install the wiring harness to the water outlet housing stud.
5. Install the radiator inlet hose to the water outlet housing.
6. Use the J 38185 in order to reposition and install the hose clamp to the water outlet housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
7. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the upper intake manifold with the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) in Engine Mechanical - 3.6L (LY7).
3. Disconnect the surge tank hose from the thermostat.
4. Remove the coolant pipe/thermostat housing bolt (1).
5. Remove the coolant pipe bolt (3).
6. Remove the coolant inlet pipe from the thermostat housing.
7. Remove and discard the coolant pipe O-ring seal (2).
8. Remove the thermostat bolts.
9. Remove the thermostat and discard the thermostat seal.

1. Install the thermostat with a NEW thermostat seal.
2. Install the thermostat bolts. Tighten: Tighten the thermostat bolts to 10 N.m (89 In. Lbs.).
3. Install the coolant pipe, NEW seal (2), and fasteners (1 and 3). Refer to «Radiator Pipe Replacement - Outlet»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Install the surge tank hose to the thermostat.
5. Install the upper intake manifold with the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) in Engine Mechanical - 3.6L (LY7).
6. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

J 38185 Hose Clamp Pliers. See Special Tools .

1. Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
2. Partially drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Use the J 38185 in order to reposition the hose clamp from the water outlet housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
4. Remove the radiator inlet hose from the water outlet housing.
5. Reposition the wiring harness from the water outlet housing stud.
6. Remove the water outlet housing bolt and the stud.
7. Remove the water outlet housing and the gasket.
8. Remove the thermostat.
9. Clean and Inspect the water outlet housing gasket mating surfaces.

1. Install the thermostat.
2. Install the gasket and the water outlet housing.
3. Install the water outlet housing bolt and the stud to the water outlet housing. Tighten: Tighten the bolt and the stud to 27 N.m (20 Ft. Lbs.).
4. Install the wiring harness to the water outlet housing stud.
5. Install the radiator inlet hose to the water outlet housing.
6. Use the J 38185 in order to reposition and install the hose clamp to the water outlet housing. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
7. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) in Engine Controls - 3.6 L (LY7).
3. Remove the radiator outlet hose from the radiator outlet pipe. Refer to «Radiator Hose Removing/Installing Coolant Pipe/Thermostat Housing Bolts Replacement - Outlet (3.8L)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (3.6L)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the radiator outlet pipe bracket to transmission retaining bolt (3).
5. Remove the radiator outlet pipe bracket to thermostat housing retaining bolt (1).
6. Remove the radiator outlet pipe from the thermostat housing.
7. Remove the radiator outlet pipe O-ring from the radiator outlet pipe.

1. Install the radiator outlet pipe O-ring to the radiator outlet pipe.
2. Install the radiator outlet pipe to the thermostat housing.
3. Install the radiator outlet pipe bracket to transmission retaining bolt (3).
4. Install the radiator outlet pipe bracket to thermostat housing retaining bolt (1).
5. Install the radiator outlet hose from the radiator outlet pipe. Refer to «Radiator Hose Replacement - Outlet (3.8L)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Hose Replacement - Outlet (3.6L)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) in Engine Controls - 3.6 L (LY7).
7. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

EN 46104 Water Pump Pulley Holding Tool

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the generator drive belt. Refer to «Drive Belt Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) in Engine Mechanical - 3.6L (LY7).
3. Use the EN 46104 (1) in order to retain the water pump pulley.
4. Remove the water pump pulley bolts.
5. Remove the water pump pulley.
6. Remove the water pump bolts.
7. Remove the water pump.
8. Remove and DISCARD the water pump seal.
9. Carefully clean the water pump sealing surfaces.

1. Install a NEW water pump seal.
2. Install the water pump.
3. Install the water pump bolts. Tighten: Tighten the water pump bolts to 10 N.m (89 In. Lbs.).
4. Install the water pump pulley and the water pump pulley bolts.
5. Use the EN 46104 (1) in order to retain the water pump pulley.
6. Install the water pump pulley bolts. Tighten: Tighten the water pump pulley bolts to 12 N.m (106 In. Lbs.).
7. Install the generator drive belt. Refer to «Drive Belt Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) in Engine Mechanical - 3.6L (LY7).
8. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Reposition the accessory wiring junction block.
3. Loosen the water pump pulley bolts.
4. Remove the drive belt. Refer to «Drive Belt Replacement (L26)»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
5. Remove the water pump pulley bolts.
6. Remove the water pump pulley.
7. Remove the power steering pump mounting bolts and reposition. Refer to «Power Steering Pump Replacement (3.8L V6)»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) or «Power Steering Pump Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
8. Remove the water pump bolts.
9. Remove the water pump.
10. Remove the water pump gasket.
11. Clean and inspect the water pump gasket mating surfaces.

1. Install the gasket and the water pump.
2. Install the water pump bolts. Tighten: Tighten the long water pump bolts to 34 N.m (25 Ft. Lbs.). Tighten the short water pump bolts to 22 N.m (16 Ft. Lbs.).
3. Install the water pump pulley.
4. Install the water pump pulley bolts. Tighten: Tighten the bolts to 13 N.m (115 In. Lbs.).
5. Install the power steering pump. Refer to «Power Steering Pump Replacement (3.8L V6)»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) or «Power Steering Pump Replacement (LY7)»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
6. Install the drive belt. Refer to «Drive Belt Replacement (L26)»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
7. Install the accessory wiring junction block.
8. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the radiator drain plug by unscrewing counter clockwise and pulling straight out. The seal usually comes out attached to the plug.
3. Clean the drain and the drain plug.

1. Install the seal on the drain plug stem.
2. Install the drain plug by screwing in a clockwise direction. Make sure that the body is fully seated in the side tank.
3. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the right and the left engine mount struts. Refer to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) and «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
3. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) in Engine Controls - 3.8L.
4. Remove the powertrain control module (PCM) harness clip from the fan shroud.
5. Remove the transmission oil cooler lines from the lower fan shroud clip and reposition the oil cooler lines aside.
6. Remove the fan shroud clip from the condenser tubes.
7. Remove the cooling fan shroud bolts.
8. Remove the bolt that connects the fan shroud to the condenser hold down bracket.
9. Remove the radiator upper bracket bolts and brackets.
10. Disconnect the engine cooling fan motors electrical connectors.
11. Remove the cooling fans electrical harness from the fan shroud clips.
12. Remove the cooling fan shroud.
13. Remove the right and left engine cooling fan blade nut.
14. Remove the right and left engine cooling fan blade.
15. Inspect the cooling fan blades for the following conditions: Bent or cracked cooling fan blades Smoothness of the cooling fan blade mating surfaces Remove burrs or other imperfections as necessary
16. Remove the right and left engine cooling fan motor bolts.
17. Remove the right and left engine cooling fan motor from the fan shroud.
18. Remove the transmission oil cooler line retaining clip from the bottom of the fan shroud.
19. Remove the cooling fan motors electrical harness retaining clips from the fan shroud.
20. Remove the cooling fan motor heat shield retainers.
21. Remove the cooling fan motor heat shield.

1. Install the right and left engine cooling fan motor to the fan shroud.
2. Install the right and left cooling fan motor bolts. Tighten: Tighten the bolts to 6 N.m (53 In. Lbs.).
3. Install the right and left engine cooling fan blade.
4. Install the right and left engine cooling fan blade nut. Tighten: Tighten the nuts to 6 N.m (53 In. Lbs.).
5. Install the transmission oil cooler line retaining clip to the bottom of the fan shroud.
6. Install the engine cooling fan motor heat shield.
7. Install the engine cooling fan motor heat shield push in retainers.
8. Install the cooling fan motors electrical harness retaining clips to the fan shroud.
9. Install the cooling fan shroud.
10. Install the cooling fan shroud bolts. Tighten: Tighten the bolts to 10 N.m (89 In. Lbs.).
11. Install the cooling fan motors electrical harness to the fan shroud clips.
12. Connect the engine cooling fan motors electrical connectors.
13. Install the fan shroud clip to the condenser tubes.
14. Install the bolt that connects the fan shroud to the condenser hold down bracket. Tighten: Tighten the bolts to 6 N.m (53 In. Lbs.).
15. Install the radiator upper support brackets and bolts that connect to the fan shroud. Tighten: Tighten the bolts to 10 N.m (89 In. Lbs.).
16. Install the PCM harness clip to the fan shroud.
17. Install the transmission oil cooler lines to the retainer clip at the bottom of the cooling fan shroud.
18. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) in Engine Controls - 3.8L.
19. Install the right and left engine mount struts. Refer to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) and «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
20. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
21. Inspect cooling fan's for proper operation.

Scheme 5

Fan Shroud Replacement (LY7)

J 38185 Hose Clamp Pliers. See Special Tools .

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) for the 3.8L engine or to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) for the 3.6L (LY7) engine.
3. Drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the right and the left engine mount struts. Refer to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) and «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) for the 3.8L engine or to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) for the 3.6L (LY7) engine and «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) for the 3.6L (LY7) engine.
5. Use J 38185 to remove the inlet hose clamp from the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
6. Remove the inlet hose from the radiator.
7. Remove the powertrain control module (PCM) harness clip from the fan shroud.
8. Remove the transmission oil cooler lines from the retainer clip at the bottom of the cooling fan shroud.
9. Remove the fan shroud clip from the condenser tubes.
10. Remove the bolt that connects the fan shroud to the condenser hold down bracket.
11. Remove the air deflectors from the top of the radiator.
12. Remove the cooling fan shroud bolts.
13. Remove the coolant reservoir hose from the radiator overflow neck.
14. Remove the radiator upper support brackets and bolts that connect to the fan shroud.
15. Disconnect the engine cooling fan motors electrical connectors.
16. Remove the cooling fan motors electrical harness from the fan shroud clips.
17. Remove the cooling fan shroud.
18. Use J 38185 to remove the outlet hose clamp from the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
19. Remove the outlet hose from the radiator.
20. Disconnect the transaxle oil cooler pipes from the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/lacrosse/i-2004-2009/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-2-of-2) for the 4T65-E transaxle.
21. Tilt the top of the radiator rearward.
22. Remove the condenser hold down bracket (1) from the radiator.
23. Lift the condenser from the mounting tabs on the radiator (2). Position the condenser aside.
24. Remove the radiator.

1. Install the radiator to the lower mounts.
2. Install the condenser to the mounting tabs on the radiator (2).
3. Install the condenser hold down bracket (1) to the radiator and condenser.
4. Install the outlet hose to the radiator.
5. Use J 38185 to install the outlet hose clamp to the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
6. Connect the transaxle oil cooler pipes to the radiator. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(/buick/lacrosse/i-2004-2009/remont/automatic-trans/#automatic-transaxle-4t65-e-introduction-2-of-2) for the 4T65-E transaxle.
7. Install the cooling fan shroud.
8. Install the cooling fan motors electrical harness to the fan shroud clips.
9. Connect the engine cooling fan motors electrical connectors.
10. Install the fan shroud clip to the condenser tubes.
11. Install the cooling fan shroud bolts. Tighten: Tighten the bolts to 10 N.m (89 In. Lbs.).
12. Install the radiator upper support brackets and bolts that connect to the fan shroud. Tighten: Tighten the bolts to 6 N.m (53 In. Lbs.).
13. Install the air deflectors to the top of the radiator.
14. Install the bolt that connects the fan shroud to the condenser hold down bracket. Tighten: Tighten the bolt to 6 N.m (53 In. Lbs.).
15. Install the PCM harness clip on to the fan shroud.
16. Install the inlet hose to the radiator.
17. Use J 38185 to install the inlet hose clamp to the radiator. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system__special-tools) .
18. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) for the 3.8L engine or to «Air Cleaner Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) for the 3.6L (LY7) engine.
19. Install the coolant reservoir hose to the radiator overflow neck.
20. Install the right and the left engine mount struts. Refer to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) and «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) for the 3.8L engine or to «Engine Mount Strut Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) for the 3.6L (LY7) engine and «Engine Mount Strut Replacement - Right»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) for the 3.6L (LY7) engine.
21. Install the transmission oil cooler lines to the retainer clip at the bottom of the cooling fan shroud.
22. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
23. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) .
24. Adjust the transaxle fluid level.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the lower air deflector fog lamp access panels.
3. Remove the lower air deflector retainers (1).
4. Remove the lower air deflector center retainer (2).
5. Remove the lower air deflector bolts (3).
6. Remove the lower air deflector screws (4).
7. Remove the right and left side lower front fender liner screws from the lower air deflector.
8. Remove the lower air deflector.

1. Install the lower air deflector. Install the lower air deflector bolts (3). Tighten: Tighten the bolts to 20 N.m (15 Ft. Lbs.).
2. Install the lower air deflector center retainer (2).
3. Install the lower air deflector retainers (1).
4. Install the lower air deflector screws (4). Tighten: Tighten the screws to 2 N.m (18 In. Lbs.).
5. Install the right and left side lower front fender liner screws to the lower air deflector. Tighten: Tighten the screws to 2 N.m (18 In. Lbs.).
6. Lower the vehicle.

1. Remove the upper air baffle. Refer to «Radiator Air Baffle and Deflector Replacement - Upper»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the right and left side air baffle push-in retainers.
3. Remove the right and left side air baffles.

1. Install the right and left side air baffles to the vehicle.
2. Install the right and left side air baffle push-in retainers.
3. Install the upper air baffle. Refer to «Radiator Air Baffle and Deflector Replacement - Upper»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Open the hood.
2. Remove the retainers from the upper air deflector.
3. Remove the upper air deflector.

1. Install the upper air deflector.
2. Install the retainers to the upper air deflector.
3. Close the hood.

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

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

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Disconnect the coolant heater cord from the coolant heater.
3. Loosen the bolt at the coolant heater but do not remove.
4. Remove the coolant heater.
5. Remove and clean any burrs, compound, paint, or rough spots from the core plug hole.

1. Apply a coat of GM P/N 12346004, (Canadian P/N 10953480) thread sealant with Teflon or equivalent to the O-ring and clean the surface of the plug opening.
2. Install the coolant heater by pushing tight to the block.
3. Install the coolant heater so the element is at the 9 o'clock position (2).
4. Tighten the coolant heater bolt until both locking wings draw tight against the inner wall of the engine block. Tighten: Tighten the bolt to 2 N.m (17 In. Lbs.).
5. Connect the coolant heater cord to the coolant heater.
6. Fill the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the coolant heater cord retainer from the upper radiator support.
2. Cut the coolant heater cord straps at the engine wiring harness.
3. Disconnect the coolant heater cord from the coolant heater.
4. Remove the coolant heater cord from the vehicle.

1. Install the coolant heater cord to the vehicle.
2. Connect the coolant heater cord to the coolant heater.
3. Install a new coolant heater cord straps at the engine wiring harness.
4. Install the coolant heater cord retainer to the upper radiator support.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the coolant heater power supply cord from the coolant heater (1).
3. Disconnect the coolant heater cord clip (2) from the coolant heater cord.
4. Lower the vehicle.
5. Disconnect the coolant heater cord clips (3, 4) from the following: The engine wiring harness conduit The engine oil level indicator tube
6. Remove the coolant heater cord from the vehicle.

1. Position the coolant heater power supply cord to the engine.
2. Route the coolant heater cord along the engine wiring harness conduit.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Connect the coolant heater cord to the coolant heater (1).
5. Secure the coolant heater cord clip (2) to the coolant heater cord.
6. Lower the vehicle.
7. Secure the coolant heater cord clips (3, 4) to the following: The engine wiring harness conduit The engine oil level indicator tube

Cooling Fan Control

The engine cooling fan system consists of 2 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 from the underhood fuse block. The ground path is provided at G100.

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 fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the 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 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 supplies the ground path for the 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 fan 2 relay and the fan 3 relay through the high speed cooling fan relay control circuit. This energizes the fan 2 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the fan 3 relay coil is energized closing the relay contacts and provides battery positive voltage from the 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 air conditioning (A/C) is requested and the ambient temperature is more than 4°C (39°F)
3. A/C refrigerant pressure exceeds 1241 kPa (180 psi)
4. After the vehicle is shut off if the engine coolant temperature at key-off is more than 117°C (242°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 exceeds approximately 105°C (221°F)
2. A/C refrigerant pressure exceeds 1655 kPa (240 psi)
3. When certain DTCs set
4. The PCM will command the cooling fans ON at any vehicle speed when the engine coolant temperature exceeds approximately 123°C (254°F)

Engine Coolant Indicators

TEMP

1. The HOT COOLANT INDICATOR illuminates when the powertrain control module (PCM) determines that the coolant temperature is greater than 128°C (262°F). The HOT COOLANT INDICATOR control circuit is grounded by the PCM, causing the HOT COOLANT INDICATOR to illuminate.
2. The IPC performs the displays test at the start of each ignition cycle. The HOT COOLANT INDICATOR will illuminate during this test.

Coolant Heater

The optional engine coolant heater (RPO KO5) operates using 110-volt AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather -29°C (-20°F). The coolant heater helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. A weather shield on the cord is provided to protect the plug when not in use.

The cooling system'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 coolant does not flow to the radiator until the thermostat opens. This allows the engine to warm quickly.

Cooling Cycle

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

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

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

Coolant is also directed to the throttle body with RPO L26. There the coolant circulates through passages in the casting. During initial warm-up, the coolant assists in warming the throttle body.

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

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

Coolant

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

Radiator

The radiator is a heat exchanger consisting of a core and 2 tanks. The aluminum core is a tube and fin crossflow design that extends from the inlet tank to the outlet tank. Fins are placed around the outside of the tubes to improve heat transfer to the atmosphere.

The inlet and outlet tanks are a molded, high temperature, nylon reinforced plastic material. A high temperature rubber gasket seals the tank flange edge to the aluminum core. The tanks are clamped to the core with clinch tabs. The tabs are part of the aluminum header at each end of the core.

The radiator also has a drain cock located in the bottom of the left hand tank. The drain cock unit includes the drain cock and drain cock seal.

Heat is removed from the coolant as the coolant passes through the radiator. The fins on the core transfer heat from the coolant passing through the tubes. Air passing between the fins absorbs the heat and cools the coolant.

Pressure Cap

The pressure cap seals and pressurizes the cooling system. The cap contains a blow off, or pressure valve and a vacuum, or an atmospheric valve

1. The pressure valve is held against the seat by a spring that protects the radiator by relieving pressure that exceeds 15 psi.
2. The vacuum valve is held against the seat by a spring that permits opening of the valve to relieve vacuum created when the cooling system cools. The vacuum, if not relieved, might cause the radiator to collapse.

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

The pressure in the cooling system can get too high. When the pressure exceeds the strength of the spring, the pressure valve rises, venting the excess pressure.

As the engine cools, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum causes the vacuum valve to open. This equalizes the pressure in the cooling system with the 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 tank 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 within the cooling system gets too high, the pressure valve in the pressure cap will open. This allows the coolant, which has expanded due to heat, 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 the elimination of 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 cooling system capability. Deflectors are installed under the vehicle to redirect airflow beneath the vehicle and through the radiator to increase engine cooling. Air baffles are also used to direct airflow through the radiator and increase cooling capability. Air seals prevent air from bypassing the radiator and A/C condenser, and prevent recirculation of hot air for better hot weather cooling and A/C condenser performance.

Water Pump

The water pump is a centrifugal vane impeller type pump. The pump consists of a housing with coolant inlet and outlet passages and an impeller. The impeller is mounted on the pump shaft and consists of a series of flat or curved blades or vanes on a flat plate. When the impeller rotates, the coolant between the vanes is thrown outward by centrifugal force.

The impeller shaft is supported by one or more sealed bearings. The sealed bearings never need to be lubricated. Grease cannot leak out, dirt and water cannot get in as long as the seal is not damaged or worn.

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

Thermostat

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

When the coolant temperature is below the rated thermostat opening temperature, the thermostat valve remains closed. This prevents circulation of the coolant to the radiator and allows the engine to warm up. After the coolant temperature reaches the rated thermostat opening temperature, the thermostat valve will open. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. The thermostat also provides a restriction in the cooling system, 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.

Special Tools

Special Tools Illustration Tool Number/Description EN 46104 Water Pump Pulley Holding Tool GE 47716 Vac-N-Fill Coolant Refill Tool GE 47827 Socket J 24460-01 Cooling System Pressure Tester J 24731 Tempil Stick J 26568 Coolant and Battery Fluid Tester J 28410 Gasket Remover J 38185 Hose Clamp Pliers J 42401 Radiator Cap/Surge Tank Test Adapter

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

See also:
• Diagnostic System Check - Vehicle
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Connector Repairs
• Control Module References
• Checking Aftermarket Accessories
• Heater Core Replacement
• Engine Coolant/Water in Transmission
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Coolant in Combustion Chamber
• Coolant in Engine Oil
• Coolant in Combustion Chamber
• Coolant in Engine Oil
• Lower Engine Noise, Regardless of Engine Speed
• Lower Engine Noise, Regardless of Engine Speed
• Cylinder Leakage Test
• Cylinder Leakage Test
• Circuit Testing
• Knock Sensor (KS) 1 Replacement
• Fastener Notice
• Capacities - Approximate Fluid
• Engine Block Disassemble
• Brace Replacement - Front Fender Upper Diagonal
• Fastener Tightening Specifications
• Lifting and Jacking the Vehicle
• Air Cleaner Assembly Replacement
• Wiper Motor, Wiper System Module Replacement
• Battery Negative Cable Disconnect/Connect Procedure (L26)
• Intake Manifold Replacement - Lower
• Power Steering Pump Replacement (3.8L V6)
• Transmission Fluid Cooler Line Quick Connect Fitting
• DTC P0480, P0481, P0691, P0692, P0693, or P0694
• Cooling System Connector End Views
• Engine Overheating (LY7)
• Symptoms - Engine Cooling
• 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 (LY7)
• Flushing
• Special Tools