OEM GMC Sierra 3500 Classic Exhaust Manifold

GMC Sierra 3500 Classic Exhaust Manifold Parts Questions & Experts Answers

• Exhaust Manifold, Passenger Side
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  Q: How to replace the right side exhaust manifold (4.8L, 5.3L, 6.0L, and 6.2L) on GMC Sierra 3500 Classic?

  A: The right side Exhaust Manifold replacement process (4.8L, 5.3L, 6.0L, and 6.2L) begins with heated Oxygen Sensor (HO2S) removal followed by vehicle suspension and subsequent removal of the Catalytic Converter to Exhaust Manifold nuts and right wheelhouse liner before disconnecting Spark Plug Wires and Ignition Coils and extracting the engine block's oil level indicator tube bolt and tube. Begin the procedure by taking off the Catalytic Converter to Exhaust Manifold nuts along with removing the right wheelhouse liner and disconnecting Spark Plug Wires from spark plugs through boot twisting by half turn and boot pulling. After removing the ignition coils follow by taking out both the oil level indicator tube bolt (419) along with the tube (420) from the engine block. Discard the Exhaust Manifold Gasket and seal as you proceed to take out the Exhaust Manifold bolts and Exhaust Manifold itself. When replacing the Exhaust Manifold users must remove all Exhaust Manifold heat shield bolts while simultaneously disconnecting its shield from the exhaust pipe. Install the Exhaust Manifold heat shield by positioning it then fastening its bolts to 9 n.m (80 lb in). Prepare each Exhaust Manifold bolt thread and apply gm p/n 12345493 threadlock (Canadian P/N 10953488) as a 5 mm (0.2 in) thick strip on the threads. Position the new Catalytic Converter seal alongside the Exhaust Manifold Gasket and Exhaust Manifold onto the cylinder head while verifying appropriate seating of the Catalytic Converter seal. Begin by installing the Exhaust Manifold bolts with an initial torque of 15 n.m (11 lb ft) that progresses from the center toward the outside bolts by alternating between sides before conducting a final torque of 20 n.m (15 lb ft) applying the same alternating sequence. A flat punch should be used to bend the gasket tab at the cylinder head edge while inspecting the o-ring seal (421) for damage before either replacement or lubrication of the o-ring with clean engine oil. Install the oil level indicator tube (420) while tightening bolt (419) to 25 n.m (18 lb ft). Seamlessly reconnect the Spark Plug Wires with the spark plugs and ignition coils through a boot seating check by applying side pressure. Complete the procedure by putting back the right wheelhouse liner while the vehicle is fully raised then support it before you install the Catalytic Converter and Exhaust Manifold nuts which need tightening to 50 n.m (37 lb ft). Finish by lowering the vehicle partially so you can work through the wheel opening and place the ho2s.