Oldsmobile 90537679 Engine Exhaust Manifold Assembly

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Disconnect the cable from the negative battery terminal. If equipped, remove the AIR valve bracket nut, then remove the bolts and disconnect the AIR pipe from the exhaust manifold. Note: It isn't necessary to detach the hose from the AIR valve. Remove the exhaust manifold heat shield. Raise the vehicle and support it on jackstands. Detach the exhaust pipe from the manifold. Follow the lead from the oxygen sensor up to its electrical connector, then unplug the connector. Also detach the lead from its retaining clip. Remove the exhaust manifold mounting nuts and detach the manifold from the cylinder head. Using a scraper, thoroughly clean the mating surfaces on the cylinder head, manifold and exhaust pipe. Remove the residue with a solvent such as acetone or lacquer thinner. Check that the mating surfaces are perfectly flat and not damaged in any way. A warped or damaged manifold may require machining or, if severe enough, replacement. Install the new gasket to the cylinder head studs and place the manifold on the cylinder head. Tighten the nuts evenly, working from the center outwards, to the specific torque. Connect the exhaust pipe to the manifold and tighten the nuts evenly to the specific torque. The remainder of installation is the reverse of the removal steps.

Before you can even think of disposing the exhaust manifold, unbend the cable that connects the negative battery terminal, then get rid of the air intake duct assembly and the heat shield that was earlier fixed on the exhaust manifold. Remove both the LSB and the HFM plug connections, lift the car and safely install it on jackstands. The front part of the exhaust pipe can now be cut off; the nuts that hold the exhaust pipe to the mounting bracket are best soaked with penetrating oil first, and the wiring of the oxygen sensor on the heat shield should be disconnected. Then, cut off the exhaust manifold mounting nuts, and disconnect the exhaust pipe from the manifold: For installation clean the mating surfaces on the cylinder head, manifold and exhaust pipe by scraping off any debris then using a rag and brake system cleaner to clean the surface further. Inspection to ensure that the mating surface is flat and that there is no sign of chipping, if there is evidence of warping or chipping then probably the two would require to be machined or changed respectively. New gasket needs to be set on the cylinder head studs and then manifold needs to be placed on the cylinder head studs, nuts needs to be tight from center to outer circle with the recommended torque value. Join the exhaust pipe with the manifold then torque the nuts that are tighten an even manner to the standard torque. Perform exhaust leaks check and then reconnect the battery and start the engine once again but before doing so reverse the above steps of removal.

Connect the exhaust pipe to the manifold and tighten the nuts evenly to the specified torque. The remainder of the installation is the reverse of the removal steps. Reconnect the battery, run the engine, and check for exhaust leaks.

The first step is to disconnect the cable from the negative battery terminal.

Remove the oil dipstick and dipstick tube, the coolant extension housing, power steering pipe bracket, front exhaust pipe assembly, and the oil filter housing assembly.

After disconnecting the battery, raise the vehicle and support it securely on jackstands.

Position a new gasket in place and slip the exhaust manifold over the studs on the cylinder head.

Using a scraper, thoroughly clean the mating surfaces on the cylinder head, manifold, and exhaust pipe. Remove any residue with a solvent such as acetone or lacquer thinner. Check that the mating surfaces are perfectly flat and not damaged in any way. A warped or damaged manifold may require machining or replacement.

Connect the exhaust pipe to the manifold and tighten the nuts evenly to the specific torque.