GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2009 🢒 XLR 🢒 Engine 🢒 Engine Mechanical - 4.6L (LH2) 🢒 Intake Manifold Replacement

Removal Procedure
  1. Remove the fuel rail assembly. Refer to Fuel Injection Fuel Rail Assembly Replacement.
  2. Loosen the plenum duct clamp at the front of the intake manifold.

    3. Object Number: 928175 Size: SH
  3. Remove 10 bolts attaching the intake manifold to the cylinder heads.
  4. Remove the intake manifold by using an upward lifting motion at the rear of the manifold assembly.
  5. Clean and inspect the intake manifold. Refer to Intake Manifold Cleaning and Inspection.

Installation Procedure

    Object Number: 490830 Size: SH
  1. Lightly lubricate the inside edge of the rubber plenum duct.

    2. Object Number: 490825 Size: SH
  2. Clean any debris from the cylinder head and intake manifold.
  3. Install the new gaskets to the intake manifold.

    4. Note: Ensure the PCV valve hose is firmly connected to the fitting at the rear of the intake manifold, prior to installation.

  4. Place the intake manifold in position by completing the following:
    5. 4.1. Position the front of the intake manifold (1) into the plenum duct (2).
    4.2. Position the rear of the intake manifold (1) downward on to the cylinders heads.

    Object Number: 490821 Size: SH
  5. Loosely install the 10 bolts attaching the intake manifold (1) to the cylinder heads.

    6. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 797947 Size: SH
  6. Tighten the intake manifold bolts in sequence (1-10) to 10 N·m (89 lb in).

    7. Object Number: 522666 Size: SH
  7. Ensure that the plenum duct is fully attached to the front of the intake manifold. Tighten the plenum duct clamp (1) to 2.25 N·m (20 lb in).
  8. Install the fuel rail assembly. Refer to Fuel Injection Fuel Rail Assembly Replacement.
  9. To clean, turn the ignition switch to the ON position for 2 seconds, then turn to the OFF position for 10 seconds. Again turn to the ON position and check for fuel leaks.
  10. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement.