GM 97363571
Intake Manifold

If to replace the Intake Manifold, one must remove the Throttle Body and fuel injectors. The electrical connectors of the manifold absolute pressure (MAP) sensor and Knock Sensor should be disconnected, and then the Knock Sensor harness connector removed from the Intake Manifold and laid back. If the vehicle has vacuum assisted brakes, unbolt the vacuum brake booster hose from the back of the Intake Manifold and the positive crankcase ventilation (PCV) hose. Next, do an extraction of the MAP Sensor and the evaporative emission (EVAP) purge solenoid vent tube which is taken off the solenoid and vapor pipe. Remove the evap purge solenoid bolt, solenoid, and isolator from the Intake Manifold, and then loosen and remove the Intake Manifold with the gaskets. The old gaskets should be discarded. If necessary, clean and check the Intake Manifold. For installation, install new Intake Manifold gaskets on the Intake Manifold, then install the manifold. While on the head, apply a 5 mm thick band of threadlocker to the bolt threads of the Intake Manifold bolts and tighten in the same sequence to 5 nm (44 inch lbs.) for the first and a final pass to 10 nm (89 inch lbs.). Mount the evap purge solenoid , isolator as well as bolt the isolator to the Intake Manifold using a bolt tightened to 10nm (89 inch lbs). Replace the evap purge solenoid vent tube attached back to the solenoid and vapor pipe. Lightly oil the MAP Sensor seal with clean engine oil before mounting the MAP Sensor onto Intake Manifold. Install the pcv hose back onto the rear of the Intake Manifold, as well as the vacuum brake booster hose if necessary. Route the electrical harness to its desired location over the engine and place the Knock Sensor harness electrical connector to the Intake Manifold, map sensor and Knock Sensor connectors. Last, we install the fuel injectors and Throttle Body.

Engine replacement requires drivers to first loosen the intake manifold sight shield bolt before pulling out the sight shield from its retainer on 4.8L, 5.3L, and 6.0L (RPO LQ4) engines. You should remove the sight shield retainer bolts and retainer only if needed. Follow these directions when installing by first installing the sight shield retainer along with its bolts then tighten everything to 5 Nm torque (44 inch lbs). The MAP sensor wire harness connector must be kept free from contact when installing to prevent engine power degradation and sensor damage. To finish installation secure the intake manifold sight shield to its retainer with a bolt torque set at 10 Nm (89 inch lbs.).

Before replacing the Intake Manifold, loosen the clamps at the Throttle Body and air cleaner, then remove the air cleaner outlet duct. Unsnap and pull off Intake Manifold sight shield from stud and bracket, and, if necessary, remove sight shield bracket nuts and bracket. Release the fuel system pressure and disconnect the fuel feed and the return pipe. Remove the clips of the engine harness from the studs on the front of the dash and the wheelhouse splash shield and separate from one another. Remove the pressure cycling switch , surge tank switch , and mass airflow(speed) sensor. Reposition the branch of the engine harness to the top of the engine, and dismantle the connector position assurance (CPA) retainer at the ignition coil harness, and disconnect the manifold absolute pressure (MAP) sensor, ignition coil harness, and engine coolant temperature (ECT) sensor. I will extract the engine harness bolt and studs, remove cpa retainer at the ignition coil harness and remove the generator, injector harness, ignition coil harness, electronic throttle control (ETC), and purge valve solenoid. Move the engine harness back on the driver's side of the engine purse removal bypass valve vacuum hose from Intake Manifold, connect evaporative emission (EVAP) tube from the purge solenoid, unclip evap tube from the Fuel Rail, and the connect it to the vent pipe at the rear of the engine prior to tuging the evap tube. If replacement of Intake Manifold calls for removal, remove the Fuel Rail studs and Fuel Rail. Do not use any tool to probe beneath the gasket surface once removing bolts from the Intake Manifold and then the Intake Manifold unless they are at least three weeks old. Remove the bottom sides of the Intake Manifold gaskets and the end seals along with the removal of the splash shield that is reusable. Check and clean the Intake Manifold prior to installation. If replacing the Intake Manifold, put the splash shield in so that it snap fits between the cylinder heads and install the new Intake Manifold end seals and side gaskets, aligning the gasket tabs with holes in the head gasket and slots in the Intake Manifold end seals. Install Intake Manifold with a thread lock, gm p/n 12345382 (Canadian P/N 10953489) or equivalent, to a minimum of 8 threads of the Intake Manifold bolts. Install the Intake Manifold bolts and tighten it through the specified order in four goes: first to 5 nm (44 inch lbs.), second to 8 nm, (71 inch lbs.), third to 12 nm, (106 inch lbs.). And finally to 15 nm, (11 ft lbs.). Lubricate the Fuel Injector O-Ring seals with clean oil engine and fit them on the spray tip of each injector. When replacing the Intake Manifold, install Fuel Rail and pull the Fuel Rail studs up to 12 nm(106 inch lbs.). Reconnect the evap tube back with the vent pipe at rear side of the engine, clip it to the Fuel Rail, and the other end output to the purge solenoid. Install the bypass lave vacuum hose to the Intake Manifold, place the engine harness on the engine compartment, and connect the disregard valve solenoid , generator , injector harness , ignition coil harness, etc and purge valve solenoid. Install the cpa retainer at the ignition coil harness and then install the engine harness bolt and studs, tightening the bolt to 16nm (12 ft. Plus) and studs to 10 nm (89 inch. Plus). Copy link the MAP Sensor, the ignition coil harness, and the ect sensor copying and lay the cpa retainer at ignition coil harness. Take the engine harness branch and put it over the top of the engine and connect the pressure cycling switch , surge tank switch and maf sensor . Finally, connect the engine harness clip to the wheelhouse splash shield, connect the engine harness clips to the studs on the front of the dash, connect the fuel feed and return pipes, install the sight shield bracket and nuts in a 5nm (44 inch lbs.), install the sight shield to the bracket, snap the Intake Manifold sight shield to the stud, install the air cleaner outlet duct, install the clamps at the Throttle Body and air cleaner to 4 nm (35 inch lbs.).

Engineers should start replacement of the Intake Manifold on lh6, lmg, ly5, and l76 engines by dislodging the air cleaner outlet duct followed by generator removal and engine harness retainer nut extraction. The next step involves eliminating the engine harness retainer from its stud and locator. Remove the electrical harness connectors from the following components: evap canister purge solenoid , manifold absolute pressure (MAP) sensor , ignition coil harness , left side fuel injectors , throttle actuator , engine coolant temperature (ECT) sensor , and right side fuel injectors . Disassemble the engine harness clips (4, 6, 1) before securing each harness branch neatly out of reach. The process requires you to relocate the Brake Booster Vacuum Hose while disconnecting the evap canister purge tube and fuel feed line . Reconnect the Brake Booster Vacuum Hose and clamp before you put new Intake Manifold gaskets (514) in place. Position the Intake Manifold (500) while keeping the engine harness clear from obstructions. To replace the manifold remove first the Brake Booster Vacuum Hose from the Intake Manifold nipple along with the upper Intake Manifold cover nut then upper Intake Manifold cover before extracting the MAP Sensor and evap tube. Before proceeding discard the Throttle Body gasket and Fuel Injector lower o-ring seals while removing the Throttle Body and Fuel Rail. The installation process includes fitting the Brake Booster Vacuum Hose nipple to the new Intake Manifold followed by the application of clean engine oil to new Fuel Injector lower o-ring seals and the performance of forceful down pressure on both ends of the rail to set the injectors. Attach the Fuel Rail first and tighten its bolts to 10 n.m (89 lb in) before installing the Throttle Body with a new gasket along with the evap tube and purge solenoid. Place lubricant on the MAP Sensor seal before installing the MAP Sensor with its retainer followed by the upper Intake Manifold cover until it reaches a snug fit. First reconnect the Brake Booster Vacuum Hose then install new Intake Manifold gaskets and position the Intake Manifold (500) with attention to engine harness clearance. Position the Intake Manifold (500) while ensuring the engine harness remains clear then tighten its bolts (512) in sequence to 5 n.m (44 lb in) for the first pass up to 10 n.m (89 lb in) for the final pass. Finish the installation by connecting the pcv hose along with the fuel feed line as well as the evap canister purge tube . Finally reattach the loose engine harness while also reconnecting the ect sensor . Secure clips 1 and 4 and 6 of the engine harness while following specifications to install the retainer and fasten the nut with 5 n.m (44 lb in) torque setting before reattaching the generator and air cleaner outlet duct.

Tighten them in sequence to 5 N.m (44 lb in) for the first pass and 10 N.m (89 lb in) for the final pass.

Disconnect the electronic temperature control (ETC) connector and remove the positive crankcase ventilation (PCV) hose.

Remove the knock sensor harness connector and set the electrical harness aside.

Discard the intake manifold gaskets.