GM 12620308
Intake Manifold

The replacement process for lh6, lmg, ly5 and l76 intake manifolds begins by removing the air cleaner outlet duct followed by removal of the generator. The engine harness retainer nut needs detachment followed by removal of the retainer from the stud and locator. First disconnect power cables from the evap canister purge solenoid followed by the MAP Sensor and ignition coil harness and the left and right side fuel injectors and throttle actuator and ect sensor. Secure all engine harness branches to the side and move them away from the work area. You should first move the Brake Booster Vacuum Hose aside and disconnect the evap canister purge tube and fuel feed line quick connect fittings when needed. After removing the Intake Manifold you should discard the old gaskets and use adhesive foil to protect the cylinder head openings from entry of debris. To replace the Intake Manifold pull off first the Brake Booster Vacuum Hose nipple followed by the upper Intake Manifold cover and MAP Sensor and Throttle Body but discard the Throttle Body Gasket along with the Fuel Injector lower o-ring seals. Place new Intake Manifold gaskets while installing the Intake Manifold and apply sequence torque values to all bolts during installation. Reinstall all three components - the Brake Booster Vacuum Hose and fuel feed line and evap canister purge tube. Affix all engine harness connectors as well as retainer and clips while making sure each attachment point is secured. Reinstall the generator as well as the air cleaner outlet duct into position.

Reposition the brake booster vacuum hose clamp and remove the vacuum hose from the booster fitting, securing it to the intake manifold.

Disconnect the battery ground cable.

Reassemble the power steering pump bracket, install the drive belt, and reconnect the water pump inlet hose and radiator inlet hose.

Position the engine wiring harness bracket to the engine, install the bracket bolts, and secure the engine wiring harness retainers for the battery cable, engine (4, 6), and MAP sensor.

Turn ON the ignition with the engine OFF for 2 seconds, then turn it OFF for 10 seconds, and finally turn it ON again with the engine OFF to inspect for fuel leaks.

Disconnect the connectors from the EVAP canister purge solenoid, MAP sensor, ignition coil harness, left side fuel injectors, throttle actuator, right side fuel injectors, and engine coolant temperature sensor.

Install the intake manifold bolts and tighten them from the inside working outward to 10 Nm (89 lb in).

Lubricate the MAP sensor seal with clean engine oil, install the MAP sensor with a new seal, and secure it with the retainer.

Install the brake booster vacuum hose nipple to the new manifold, apply new fuel injector lower O-ring seals, lubricate them with clean engine oil, and install the fuel rail, tightening the bolts to 10 Nm.