How to Replace the Intake Manifold in a Chevy Avalanche

The fuel injectors,throttle body and fuel injection rail are part of the intake manifold assembly on the 2002 to 2005 Chevy Avalanche 1500. When removing the manifold to clean it or when replacing the manifold on the 4.8L, 5.3L or 6.0L engine, remove the entire assembly.

Instructions

Remove the Intake Manifold

1

Locate the intake manifold to the right or left of the engine, depending on the model. Disconnect knock sensor connector, the Manifold Absolute Pressure (MAP) sensor and the hose and valve from the Positive Crankcase Ventilation (PCV). Remove the accelerator control bolts and cable bracket.

2

Remove the EVAP solenoid, the isolator and the bolt. Loosen and remove the manifold bolts then remove the manifold and the gasket. Pull the manifold-to-cylinder head gaskets and discard them.

3

Clean the manifold in solvent and dry it with compressed air. Inspect the throttle body and the fuel rail bolt inserts for damaged threads or loose connections. Make sure there is no damage, cracks, wear or warping of the intake manifold.

4

Inspect the vacuum passages for restrictions or debris. Look over the assembly for any broken or damaged vacuum fittings. Check the MAP sensor mounting bore and retaining tabs to assure their good condition.

5

Examine the gasket sealing surfaces and the areas between the intake runners for damage. Make sure there is no scoring on fuel injector bores.

6

Find a straight edge on the deck surface of the manifold cylinder. Align this straight edge along at least two runner port openings.

7

Place a feeler gauge between the straight edge and the intake manifold to measure any warpage. Replace the manifold when warpage is 3mm over 200mm.

Install the Intake Manifold

8

Install the intake manifold with new intake manifold-to-cylinder head gaskets. Connect the MAP sensor.

9

Connect the EVAP isolator. Apply 89 inch pounds to tighten the bolt.

10

Tighten the intake manifold bolts in sequence starting with the center bolt on the long side opposite the front of the vehicle. Moving to the right and continuing around the top edge of the manifold, number the bolts 5, 8, 9, 3, 2, 6, 7, 10 and 4.

11

Apply 5mm band of threadlock GM P/N 12345382 to the threads of the manifold bolts. Tighten the bolts to 44 inch pounds on the first round. Make a final pass and tighten bolts to 89 inch pounds.

12

Clamp the coolant air bleed hose onto the throttle body. Replace the accelerator control bracket cable. Apply 89 inch pounds to tighten the bolts.