GM 12550122 Engine Exhaust Manifold

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After removing the exhaust manifold, the manifold and cylinder head mating surfaces should be cleaned.

Remove the cable from the negative battery terminal.

After reassembling the remaining components, it is important to check for exhaust leaks when starting the engine.

The manifold should be positioned on the cylinder head and the mounting bolts should be installed, tightening them in three equal steps.

Penetrating oil should be applied to the fastener threads.

The manifold should be placed in position and the mounting nuts should be tightened.

To remove the exhaust manifold, start by disconnecting the negative battery cable and raising the vehicle on jackstands. Apply penetrating oil to the exhaust pipe-to-manifold studs and nuts, then remove the nuts retaining the exhaust pipe(s) to the manifold(s). On the right side manifold, remove the air cleaner assembly and the heat stove pipe on TBI models. Detach the spark plug wires and brackets, and unbolt the air conditioning compressor and its bracket. Remove the oil dipstick and tube bracket. On the left side manifold, unbolt and remove the rear brace from the alternator, detach the spark plug wires, and disconnect the EGR pipe on 1996 and later models. Remove the rear power steering bracket by removing the power steering pump pulley and mounting bolts. Bend the lock tabs back, then remove the mounting bolts and separate the exhaust manifold from the cylinder head. Clean the manifold and cylinder head mating surfaces. To install the manifold, position it on the cylinder head and install the mounting bolts, tightening them in three equal steps. Finally, reassemble the remaining components and check for exhaust leaks when starting the engine.

The oxygen sensor.