GM 12580420
Intake Manifold

Starting the procedure to replace the Intake Manifold on 4.2l engine (VIN S - RPO LL8) 2006 buick rainier, 2006 chevrolet trailblazer, 2006 gmc envoy, and 2006 saab 9-7x vehicles involves first draining the fuel pressure and unbolting the Throttle Body. First disconnect the powertrain control module (PCM) by removing its retaining bolts and nuts before removing the fuel feed pipe from the Fuel Rail as well as the integral clip from the wire harness bracket. Begin by removing the engine wire harness bracket bolt and electrical harness and vacuum lines from the Intake Manifold. Disconnect the manifold absolute pressure (MAP) sensor electrical connector and crankcase ventilation hose and vacuum brake booster hose. Uninstall the generator but keep the Intake Manifold lock bolts in place before you start removing the Intake Manifold. Install the new Intake Manifold Gasket onto the Intake Manifold while tightening all bolts to 10 n.m (89 lb in) before reattaching the generator. Start by lubricating the crankcase ventilation hose then reattach the MAP Sensor electrical connector and refrill the electrical harness before reattaching the vacuum lines. Start by tightening the engine electrical harness bracket bolt to 10 n.m (89 lb in) while connecting the integral clip to its bracket. The next step is hooking up the fuel feed pipe to the Fuel Rail. Mount the pcm mounting studs with 6 n.m (53 lb in) torque setting and after that put the pcm on the studs before using retaining bolts and nuts which should reach 8 n.m (71 lb in). After threading the pcm harness connectors you should tighten the retaining bolts to 8 n.m (71 lb in). Reinstall the Throttle Body then connect the negative Battery Cable and verify leak areas by turning the ignition on with engine off for 2 seconds, followed by 10 seconds of off time and another turn on for leak inspection.

To replace the Intake Manifold (RPO L92 - First Design) (6.2L), start by removing the air cleaner outlet duct and the generator. Next, pull of the engine harness retainer nut and take of the retainer from the stud and locator. Unplug the engine harness electrical connectors of the evap canister purge solenoid , manifold absolute pressure (MAP) sensor , ignition coil harness , left side fuel injectors , throttle actuator , engine coolant temperature (ECT) sensor , right side fuel injectors. Pull off the engine harness clips and collect the harness branches to tie them back so they don't get in the way. Reposition the brake booster vacuum hose clamp, disconnect the vacuum hose from the booster hose fitting, and connect it to the Intake Manifold. Remove the evap canister purge tube and fuel feed line quick connect fittings and take out a positive crankcase ventilation (PCV) hose. Loosen and take the Intake Manifold(500) and Intake Manifold gaskets(514) off, covering the cylinder head passages to prevent the entry of debris. If replacing the Intake Manifold leave it on the table clean, re-position the brake booster vacuum hose clamp and remove the vacuum hose from the manifold nipple. Remove the upper Intake Manifold cover nut and the cover, remove the MAP Sensor retainer and MAP Sensor, then you are ready for that next step of the project. Disconnect the evap tube quick connect fitting and pull out the evap as well as purge solenoid. The Throttle Body and its gasket must be removed together with the Fuel Rail along with lifting it up to displace all the injectors from their slots. Replace the Fuel Injector lower o-ring seals and remove the brake booster vacuum hose nipple. For installation, if Intake Manifold was changed, install new brake booster vacuum hose nipple, and new Fuel Injector lower o-ring seal soaked in clean engine oil, then install Fuel Rail and tighten the bolts to 10 n.m (89 lb in). Replace a new Throttle Body Gasket, throttle body, and its bolts/nuts also tightening to 10 n.m (89 lb in). Reinstall evap tube and purge solenoid, connecting evap tube qc fitting, lubricate the MAP Sensor seal, installing the MAP Sensor and retainer. Install the upper Intake Manifold cover and nut until tight, then install the brake booster vacuum hose to the Intake Manifold nipple and tighten it. Replace new Intake Manifold gaskets (514) and remove the Intake Manifold (500) cylinder head passage covers before installation. Pretighten the Intake Manifold bolts (512) just enough until snug, then torque them according to the specified sequence to 5 n.m (44 lb in) and a final step to 10 n.m (89 lb in). Mount and attach the pcv hose, the fuel feed line and evap canister purge tube quick connect fittings, and reconnect the brake booster vacuum hose to the booster fitting. Loosen the engine parts of the harness branches and then connect the ect sensor and attach the engine harness clip to the generator bracket tightening the bolt to 9 n.m (80 lb in). Join the engine harness electrical connectors on the right and left side fuel injectors, throttle actuator, and ignition coil harness and installing the cpa retainers and as well as the engine wiring harness electrical connector to the MAP Sensor and the evap canister purge solenoid. Finally, install the engine harness retainer to the stud and locator pin, install the retainer nut to 5 n.m (44 1b in), install the generator, while finishing the job with the air cleaner outlet duct install.

Reinstall the EVAP purge solenoid, isolator, and bolt to the intake manifold, tightening the solenoid bolt to 10 N.m (89 lb in).

Reposition the brake booster vacuum hose clamp, remove the vacuum hose from the intake manifold nipple, and take off the upper intake manifold cover and MAP sensor.

Install the engine wiring harness clips to the engine harness brackets, connect the control port injector module, and finally reconnect the A/C compressor clutch and the A/C pressure switch if equipped, before installing the fuel pipes/hoses.

Place new intake manifold gaskets onto the intake manifold (500) and apply a 5 mm (0.2 inch) band of threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the intake manifold bolts (512).

Loosen and remove the intake manifold.

Reconnect the vacuum brake booster hose and its clamp.

Disconnect the fuel feed pipe from the fuel rail and the integral clip from the wire harness bracket.

Remove the PCV valve hose, power brake booster vacuum hose, and the radiator inlet hose.

Begin by removing the air cleaner outlet duct and the generator.

Remove the positive crankcase ventilation (PCV) valve hose and power brake booster vacuum hose.

Loosen the intake manifold bolts and remove the intake manifold, covering the cylinder head passages to prevent debris entry.