GM 19418928
Catalytic Converter

The first step in servicing and repairing the Exhaust Pipe requires users to elevate their vehicle before producing support. Start by removing protective shields when needed before extracting both rear exhaust system and Catalytic Converter from the vehicle. First remove the electrical connector of the Oxygen Sensor and then separate the three nuts at the Exhaust Manifold. The exhaust hanger bracket and the entire front pipe assembly with its exhaust seal need to be detached for service followed by disposal of the seal. Installation requires you to place a fresh exhaust seal on the Exhaust Manifold before installing the front pipe while securing it at the exhaust hanger bracket. Secure the three manifold exhaust nuts by using 50 nm torque value which corresponds to 39 ft. Lbs measurement. Reinstall the Oxygen Sensor electrical connector before placing the Catalytic Converter together with the rear exhaust system into position. The procedure ends with protective shield reinstallments when needed together with safety stand removal and vehicle lowering.

To service and repair the Catalytic Converter, firstly, lift and support the vehicle. First, use a protective shield to unplug the oxygen sensors discuss in the vehicle passenger compartment. Alternatively, after the vehicle has cooled for a sufficient amount of time, detach the heating shields. Next, remove right side exhaust manifolds stud nuts and also left side Exhaust Manifold stud nuts. Take out the nuts from the flange stud nuts in the junction of the rear exhaust system with the Catalytic Converter, and remove the Catalytic Converter. If replacing the Catalytic Converter, move the oxygen sensors accordingly. Start with the installation of the exhaust seals to the exhaust manifolds then the Catalytic Converter. Mount the left side Exhaust Manifold stud nuts and tighten them by 50 nm (39 ft. Lbs.), and then mount the right side Exhaust Manifold stud nuts and tighten them by 50 nm (39 ft. Lbs.). Next, tighten the nuts at the rear pipe flange to 40 nm (30 ft. Lbs.). Connect the electrical connector to the Oxygen Sensor, restore the protective shields where necessary, remove the safety stands lastly lower the vehicle.

After supporting the vehicle and transmission with proper equipment, begin the Catalytic Converter replacement process. Start by removing the transmission mount nuts to transmission support then lift the transmission away from the support before you extract the transmission support crossmember bolts and nuts leading to the crossmember's removal. The engine harness along with its oxygen sensor pigtail requires clip removal. After that disconnect the connector position assurance (CPA) retainers and oxygen sensor electrical connectors. Unclip oxygen sensor connectors both from the hose clip and transmission crossmember followed by a second disconnect of the oxygen sensor cpa retainers and electrical connectors (1, 2). Follow this sequence to remove the Catalytic Converter - first unfasten the left and right exhaust manifold pipe nuts and next disconnect the exhaust muffler nuts then remove the Catalytic Converter. You should apply gm p/n 12377953 anti-seize compound with equivalent material to old oxygen sensor threads before installation. Torque the sensors to 42 nm (31 ft. Lbs.). Drive the right and left exhaust manifold pipe nuts halfway by hand before torqueing them to 50 nm (39 ft. Lbs.). Next, install the new Catalytic Converter alongside new exhaust manifold pipe seals mounted on the exhaust manifolds. Use 40 nm (30 ft. Lbs.) torque when tightening all exhaust muffler nuts. The oxygen sensor electrical connectors (1, 2) and cpa retainers need installation before you secure the oxygen sensor electrical connectors to the hose clip and transmission crossmember. First tighten the transmission support crossmember bolts and nuts to 95 nm (70 ft. Lbs.) then reinstall the crossmember before installing the engine harness and oxygen sensor pigtail in their clips. Finally reattach the cpa retainers and oxygen sensor electrical connectors. Place the transmission mount on the support then bolt it to the transmission support nuts while torquing them to 40 nm (30 ft. Lbs.). Lower the vehicle while removing the transmission jack.

To replace the Catalytic Converter on 4.3l, 4.8l, and 5.3l, he should first raise and support the vehicle first. Unclip and disconnect the Oxygen Sensor connection as well as all electrical connectors, then remove the Oxygen Sensor clips and connect position assurance (CPA) retainers. Unclip the Oxygen Sensor electrical connectors from the hose clip and transmission crossmember, and removal remaining connectors. Take off the left exhaust manifold pipe nuts and the right ones, exhaust muffler ones, and then extract the Catalytic Converter. Remove the sensors if required. For installation, if necessary install the oxygen sensors with the use of an anti-seize gm p/n 12377953 or similar to its threads and tighten to 42nm (31 ft. Lbs.). Then there is the Catalytic Converter and new exhaust manifold pipe nuts of which you snugged the exhaust manifold pipe nuts of the right and left then tightened to 50 nm (39 ft. Lbs.). Install the exhaust muffler nuts and tighten them at a torque of 40 nm (30 ft. Lbs.). Reconnect the Oxygen Sensor electrical connectors and cpa retainers and clip the connectors to the hose clip and transmission crossmember and make sure all the connections are secure. Lastly, fasten the clip to the Oxygen Sensor pigtail and engine harness, reconnect the Oxygen Sensor electrical connector, clip the Oxygen Sensor connection to floor reinforcement if available, and drop the vehicle.

Remove the muffler.

Remove the left and right exhaust manifold pipe nuts, followed by the exhaust muffler nuts, and finally, remove the catalytic converter.

Place a new exhaust manifold pipe seal onto the exhaust manifold pipe.

Three nuts.

Position the exhaust pipe with a NEW gasket to the turbocharger, ensuring the tab on the gasket faces inward, and loosely install the bolts.

Unclip the oxygen sensor connection from the floor reinforcement if equipped, then disconnect the oxygen sensor electrical connector and remove the oxygen sensor clips from the frame.

Raise and suitably support the vehicle.

Remove the oxygen sensors.

Apply anti-seize compound GM P/N 12377953 to the old oxygen sensor threads, install the sensor, and tighten it to 42 Nm (31 ft. lbs.).