GM 12550122
Exhaust Manifold, Passenger Side

The replacement procedure for the right Exhaust Manifold on 4.8l, 5.3l, and 6.0l engines begins with Ignition Coil and Spark Plug removal followed by vehicle elevation and support. First remove Exhaust Manifold pipe nuts followed by lowering the vehicle to unlatch the Exhaust Manifold bolts and manifold with its gasket. Discard these items before moving ahead. Removing heat shield bolts along with shield components from the Exhaust Manifold becomes necessary for some repairs. Install new exhaust manifolds only if you plan to check them for cleanliness since a replacement is not needed. Use the heat shield together with its bolts to secure the Exhaust Manifold after proper bolt tightening to 9 nm (80 inch lbs.). The Exhaust Manifold bolts should receive their stated torque setting because improper installation degrades both emission performance and on-board diagnostics (OBD) ii system execution. The bolts which secure the Exhaust Manifold to the Cylinder Head must have thread-holes that are clear of dust and thread-lock compounds while excluding any sealant application from the first three threaded sections. A 5 mm (0.2 inch) wide coating of threadlock gm p/n 12345493 (Canadian P/N 10953488) or equivalent product needs to be applied to the Exhaust Manifold bolt threads. First tighten the center two bolts and then alternate between the sides when installing the Exhaust Manifold with its new gasket and bolts until they reach 15 nm (11 ft. Lbs.). Perform a final tightening phase to 25 nm (18 ft. Lbs.) by repeating the same side-to-side pattern. Use a flat punch to bend over the front part of the exposed Exhaust Manifold gasket at the right Cylinder Head. Finish by reinstalling spark plugs alongside ignition coils then raise the vehicle to put Exhaust Manifold pipe nuts in their place until they reach 50 nm (37 ft. Lbs.) torque before lowering it down.

The replacement of a 4.3l right Exhaust Manifold starts with vehicle lifting and support before removing the Exhaust Pipe from the manifold while lowering the vehicle. The next operation requires the removal of the bolt securing the oil level indicator tube. The boot of the Spark Plug needs twisting one-half turn to free it before pulling it away from the plug without wire damage. Caution must be taken when detaching Spark Plug wires from the spark plugs through boot rotation followed by boot pull-out operations before removing wires from wire retainers. Installation of the exhaust procedure starts with removing nuts that secure the secondary air injection (AIR) pipe assembly to the Exhaust Manifold. Post-nut removal proceed with removing the air pipe alongside its gasket. The Exhaust Manifold needs its bolts removed before the removal of Spark Plug wire shields and the Exhaust Manifold itself along with disposal of existing gaskets. Clean both surfaces before installing the new Exhaust Manifold gaskets when placing the Exhaust Manifold along with the Spark Plug wire shields. Apply thread lock gm p/n 12345493 or its equivalent to the Exhaust Manifold bolt threads. Then install the bolts by tightening them first to 15 nm (11 ft. Lbs.) and then to 30 nm (22 ft. Lbs.) at the final stage. The next step involves installing a fresh air pipe gasket followed by the air pipe while securing its nuts to 55 nm (18 ft. Lbs.). After this procedure, reattach the Spark Plug wires to their retainers and spark plugs. The vehicle must be raised to connect the Exhaust Pipe to the Exhaust Manifold followed by vehicle lowering while torqueing the oil level indicator tube bolt to 12 nm (106 inch lbs.).

The first step for replacing the left Exhaust Manifold involves removing the engine cover before disconnecting the engine coolant temperature (ECT) sensor. Begin the process by elevating the vehicle and taking off both the tire and fender wheelhouse extension from the left front position. The next step includes the removal of the Catalytic Converter assembly together with Spark Plug Wires and Spark Plug wire support bolts. Remove the Spark Plug wire support together with its wires then detach the 4 front Exhaust Manifold bolts by accessing through the wheelhouse and the 2 rear bolts through the engine cover opening. The Exhaust Manifold along with gaskets and Spark Plug wire shields should be taken off underneath the vehicle before cleaning all gasket surfaces. A new gasket assembly that includes Spark Plug wire shields along with bolts should be fitted to the Exhaust Manifold while the gasket tabs maintain the Exhaust Manifold bolt position. Secure the Exhaust Manifold by using torque into position through both engine cover and wheelhouse openings. Reinsert all Spark Plug Wires to the spark plugs before you install the Spark Plug wire support with its bolts and tighten them to 12 nm (106 inch lbs.). Place the fender wheelhouse extension and left front tire before adding the Catalytic Converter assembly to the installation. First lower the vehicle before you reconnect the ect sensor electrical connector and finish with installation of the engine cover.

A proper right Exhaust Manifold replacement requires vehicle elevation and Exhaust Pipe disconnection from the manifold before vehicle descent. The oil level indicator bolt needs removal before gently twisting the Spark Plug boot by 1/2 turn to free it without touching the wire itself. The Spark Plug wire removal procedure requires a 1/2 turn on the boot followed by boot extension away from the Spark Plug. The wires should then be detached from their retainers. Begin by unfastening the bolted Exhaust Manifold and continue by removing both the Exhaust Manifold itself together with the Spark Plug wire shields before discarding old gaskets and cleaning all gasket surfaces. When installing the Exhaust Manifold gather the bolts together with new gaskets and Spark Plug wire shields before placement while letting the gasket tabs secure the bolts. The installation requires the Exhaust Manifold and Spark Plug wire shields along with gm p/n 112345493 threadlock (equivalent to Canadian P/N 10953488) applied to Exhaust Manifold bolt threads when bolting in a used manifold. Torque the Exhaust Manifold bolts to 15 nm on the initial tightening and increase torque to 30 nm on the final tightening. After fixing Spark Plug Wires to their retainers and spark plugs users should raise the vehicle to attach the Exhaust Pipe to the Exhaust Manifold before lowering it. You should install the oil level indicator tube bolt followed by tightening it up to 12 nm which equates to 106 inch lbs.

Sub-assemble the NEW gaskets, spark plug wire shields, and bolts to the exhaust manifold, ensuring the exhaust manifold bolts are held in place by the tabs on the gaskets.

Raise the vehicle and remove the right front tire.

Remove the air cleaner outlet duct from the throttle body, followed by the intermediate steering shaft, and disconnect the engine coolant temperature (ECT) sensor electrical connector.

Connect the spark plug wires to the spark plugs, install the fender wheelhouse extension, and the front tire.

Reinstall the fender wheelhouse extension and the front tire.

Remove the Exhaust Gas Recirculation (EGR) valve inlet pipe from the exhaust manifold, the radiator inlet hose support bracket nut, and the nuts holding the secondary air injection (AIR) pipe to the exhaust manifold if equipped.

The spark plug wires from the spark plugs.

Reinstall the fender wheelhouse extension and left front tire, lower the vehicle, reconnect the ECT sensor electrical connector, and finally install the engine cover.