How to Replace Intake Manifold on Buick LaCrosse?

The Intake Manifold replacing details are as follows:---

Follow the details and diagrams shown below.
The procedure is mentioned for both 3.6L Engine & 3.8L Engine.


Intake Manifold
REMOVAL & INSTALLATION

3.6L Engine
Lower Manifold

1. Before servicing the vehicle, refer to the Precautions Section.
2. Turn the ignition OFF.
3. Remove the air inlet duct.
4. Remove the fuel pressure and Evaporative Emission (EVAP) hoses from the engine.
5. Disconnect the BARO sensor electrical connector.
   
   NOTE

   Do not disconnect the Engine Control Module (ECM) electrical connectors.
6. Remove the ECM bracket with the ECM and reposition aside.
7. Disconnect the purge solenoid electrical connector.
8. Disconnect the purge solenoid electrical connector.
9. Remove the wiring harness from the right side of the intake manifold.
10. Disconnect the fuel injector electrical connector.
11. Remove the throttle body electrical connector.
12. Remove the brake booster vacuum hose and check valve from the brake booster.
13. Remove the positive Crankcase Ventilation (PCV) hose from the intake manifold.
14. Remove the upper intake manifold bolts.
15. Remove the upper intake manifold.
    
    NOTE

    Do not reuse the upper to lower intake manifold gasket and the intake manifold to cylinder head sealing gaskets.
16. Remove the upper to lower intake manifold bolts.
17. Remove the fuel rail feed hose bracket bolts from the upper intake manifold.
18. Remove the fuel injector wiring harness bracket bolt from the upper intake manifold.
19. Remove the upper intake manifold from the lower intake manifold.
20. Remove and discard the upper to lower intake manifold gaskets.
21. Clean and inspect the intake manifold and the sealing surfaces. 
    
    
    
    Fig. Upper-to-lower manifold bolts-3.6L engine

To install:

NOTE

Do not reuse the upper to lower intake manifold gasket and the intake manifold to cylinder head sealing gaskets.

1. Install the NEW upper to lower intake manifold gaskets.
2. Install the upper intake manifold to the lower intake manifold.
3. Install the fuel injector wiring harness bracket bolts to the upper intake manifold. Tighten the fuel injector wiring harness bracket bolts to 89 inch lbs. (10 Nm).
4. Install the fuel rail feed hose bracket bolt to the upper intake manifold. Tighten the fuel rail feed hose bracket bolt to 89 inch lbs. (10 Nm).
5. Install the upper to lower intake manifold bolts. Tighten the upper to lower intake manifold bolts to 17 ft. lbs. (23 Nm).
6. Install the intake manifold.
7. Install the PCV hose to the intake manifold.
8. Install the brake booster vacuum hose and check valve to the brake booster.
9. Install the throttle body electrical connector.
10. Connect the fuel injector electrical connector.
11. Install the wiring harness to the right side of the intake manifold. Tighten the wiring harness bracket bolts to 89 inch lbs. (10 Nm).
12. Connect the purge solenoid electrical connector.
13. Install the ECM bracket with the ECM.
14. Connect the BARO sensor electrical connector.
15. Install the fuel pressure and EVAP hoses to the engine.
16. Install the air inlet duct.

Upper Manifold

1. Before servicing the vehicle, refer to the Precautions Section.
2. Turn the ignition OFF.
3. Remove the air inlet duct.
4. Relieve the fuel system pressure.
5. Remove the fuel pressure and Evaporative Emission (EVAP) hoses from the engine.
6. Remove the purge line from the purge line retainer.
7. Remove the fuel feed hose bracket bolt and reposition the fuel feed hose.
   
   NOTE

   Do not disconnect the Engine Control Module (ECM) electrical connectors. Do not remove the ECM from the ECM bracket.
8. Remove the ECM bracket with the ECM and position it aside.
9. Disconnect the purge solenoid electrical connector.
10. Remove the wiring harness from the right side of the intake manifold.
11. Disconnect the fuel injector electrical connector.
12. Remove the fuel injector electrical connector from the fuel injector electrical connector bracket.
13. Remove the throttle body electrical connector.
14. Remove the brake booster vacuum hose and check valve from the brake booster.
15. Remove the electrical connector for the baro sensor.
    
    
    

    

    Fig. Upper intake manifold bolt loosening/tightening sequence-3.6L engine
16. Remove the positive Crankcase Ventilation (PCV) hose from the intake manifold.
17. Remove the intake manifold bolts.
18. Remove the upper intake manifold.
19. Remove and discard the upper intake manifold gasket.
20. Clean and inspect the intake manifold and the sealing surfaces.

To install:

1. Install the intake manifold bolts. Tighten the intake manifold bolts in the order shown to 17 ft. lbs. (23 Nm).
2. Install the PCV hose to the intake manifold.
3. Install the brake booster vacuum hose and check valve to the brake booster.
4. Install the throttle body electrical connector.
5. Reconnect the electrical connector for the baro sensor.
6. Install the fuel injector electrical connector to the fuel injector electrical connector bracket.
7. Install the ECM bracket.
8. Connect the fuel injector electrical connector.
9. Install the wiring harness and bracket to the right side of the intake manifold. Tighten the wiring harness bracket bolts to 89 inch lbs. (10 Nm).
10. Connect the purge solenoid electrical connector.
    
    WARNING

    In order to prevent any possible electrostatic discharge damage to the ECM, do not touch the connector pins.
11. Install the fuel feed hose bracket and the fuel feed hose bracket bolt. Tighten the fuel feed hose bracket bolt to 89 inch lbs. (10 Nm).
12. Install the purge line to the purge line retainer.
13. Install the fuel pressure and EVAP hoses to the engine.
14. Install the air inlet duct.

3.8L Engine

Fig. Exploded view of the intake manifold and related components-3.8L engine

1. Before servicing the vehicle, refer to the Precautions Section.
2. Disconnect the negative battery cable.
3. Drain the cooling system.
4. Relieve the fuel system pressure.
5. Remove or disconnect the following:
   
   
   Fuel injector sight shield

   Air inlet duct

   Spark plug wires from the right side

   Manifold Absolute Pressure (MAP) sensor

   Vacuum lines from the intake manifold

   Fuel lines

   Fuel injector electrical connectors

   Fuel regulator vacuum line

   Fuel rail from the intake manifold

   Exhaust Gas Recirculation (EGR) heat shield

   Throttle cable bracket from the cylinder head mounting bracket and the throttle body cables

   Throttle body support bracket

   Upper intake plenum and gasket

   Thermostat housing

   Electrical connector from the Engine Coolant Temperature (ECT) sensor

   Accessory drive belt tensioner assembly

   EGR valve outlet pipe

   Lower intake manifold

To install:

Fig. Upper intake manifold torque sequence-3.8L engine

Fig. Lower intake manifold torque sequence-3.8L engine

1. Install or connect the following:
   
   
   Intake manifold using new manifold gaskets. Torque the bolts in sequence to 11 ft. lbs. (15 Nm); then, re-torque to 11 ft. lbs. (15 Nm).

   EGR valve outlet pipe

   Accessory drive belt tensioner assembly. Torque the tensioner bolts to 37 ft. lbs. (50 Nm).

   Electrical connector to the ECT sensor

   Thermostat housing

   Upper intake plenum. Torque the intake plenum bolts to 88 inch. lbs. (10 Nm).

   Throttle body support bracket

   Throttle cable bracket to the cylinder head mounting bracket and the cables to the throttle body lever

   EGR heat shield

   Fuel rail. Torque the fuel rail bolts to 88 inch. lbs. (10 Nm).

   Fuel lines

   Fuel regulator vacuum line

   Fuel injector electrical connectors

   Vacuum lines to the intake manifold

   MAP sensor

   Spark plug wires

   Fuel injector sight shield and air inlet duct

   Negative battery cable
2. Refill and bleed the cooling system.
3. Run the engine and check for leaks and proper engine operation.

These details will help.

Thanks.

FOR MORE HELP GO TO: ---

Car repair guide?

http://technoanswers.blogspot.in/2012/03/car-repair-guide.html