If the vehicle has air-conditioning, carefully examine the routing of the hoses and the mounting of the compressor, as it may be possible to remove the exhaust manifold without disconnecting the system; if uncertain, consult a GM dealer or automotive repair shop to have the system depressurized. Begin by removing the cable from the negative battery terminal, followed by the air cleaner assembly, tagging each disconnected hose with numbered tape for easier reinstallation. Next, remove the preheat tube, engine oil dipstick and dipstick tube, and the oxygen sensor. Label and disconnect the four spark plug wires, securing them to the side. Disconnect the exhaust pipe from the exhaust manifold, applying penetrating oil to corroded fastener threads if necessary, and hang the exhaust pipe from the frame with wire. Remove the exhaust manifold end bolts first, then the center bolts, and separate the manifold from the engine, followed by removing the exhaust manifold gasket. Before installing the new manifold, clean the gasket mating surfaces on the
Cylinder Head and manifold, ensuring all leftover gasket material and carbon deposits are removed. Place a new exhaust manifold gasket on the cylinder head, position the manifold, and install the mounting bolts finger tight. Tighten the bolts gradually in the specified sequence until all are at the correct torque. Finally, reinstall the remaining components in reverse order, using new gaskets where applicable, and start the engine to check for exhaust leaks between the manifold and cylinder head as well as between the manifold and exhaust pipe.