OEM 2004 Chevrolet Trailblazer Exhaust Manifold

2004 Chevrolet Trailblazer Parts Questions & Experts Answers

• Q: How to replace the exhaust manifold on a 4.2L engine on 2004 Chevrolet Trailblazer?

  A: The first step to replace a 4.2l Exhaust Manifold requires removal of the air cleaner resonator outlet duct followed by removing the transmission filler tube stud nut from the a.i.r. Adapter to shift the filler tube out of the way. Start by pulling out both the oil level indicator tube together with the Oxygen Sensor from the Exhaust Manifold. The four heat shield nuts of the manifold must be carefully detached before removing the heat shield. The vehicle elevation allows access to the Exhaust Manifold bolts but the driver must lower it afterward. First remove the Exhaust Manifold bolts which are loose before completely extracting the Exhaust Manifold along with its gasket. To install the Exhaust Manifold you should start by applying a new Exhaust Manifold Gasket then proceed to install the Exhaust Manifold itself. Use threadlock gm p/n 12345493 (Canadian P/N 10953488) on the manifold bolts before installation according to gm sequence instructions to achieve 20 nm torque for three consecutive passes. For necessary cases, mount and tighten Exhaust Manifold heat shield studs to 10 nm (89 inch lbs.). Place new anti-seize compound gm p/n 12371386 on the heat shield nuts and tighten them to 5 nm (44 inch lbs.). After raising the vehicle conduct a seal between Exhaust Pipe and manifold before finally tightening the nuts to 50 nm (37 ft. Lbs.). Replace the oil level indicator tube then position the transmission filler tube onto the a.i.r. Adapter block stud by tightening that nut to 10 nm (89 inch lbs.). You should put back the air cleaner resonator outlet duct in its proper location.