GM 14094803 Exhaust Manifold

Allow the engine to cool completely before beginning this procedure. Disconnect the negative cable from the battery, ensuring that on models equipped with the Theftlock audio system, the lockout feature is turned off before disconnecting the battery. Unplug the oxygen sensor lead, then remove the air cleaner and air duct assembly, followed by the air-inlet resonator from the upper tie bar and the lower air duct. Disconnect the upper engine mounting torque strut from the engine, then remove the nuts and bolts to disconnect the engine strut bracket from the cylinder head. Remove the drivebelt, alternator, and alternator rear support bracket. Take out the oil level dipstick and dipstick holder. Raise the front of the vehicle, support it securely on jackstands, and apply the parking brake, blocking the rear wheels to prevent rolling. Unbolt the exhaust pipe from the manifold and lower the vehicle. Remove the exhaust manifold-to-cylinder head nuts/bolts, pull the manifold off the engine, and lift it out of the exhaust pipe flange, discarding the gasket. Scrape all traces of gasket material off the exhaust manifold and cylinder head mating surfaces, being careful not to scratch or gouge the aluminum cylinder head to avoid exhaust leaks. Wipe the surfaces clean with a rag soaked in lacquer thinner or acetone, and clean all bolt and stud threads before installation using a wire brush on the manifold mounting studs and a tap for the cylinder head bolt holes. If a new manifold is being installed, transfer the oxygen sensor from the old manifold to the new one. Installation is the reverse of removal, ensuring to use a new gasket and tighten the nuts/bolts to the specified torque, working in a spiral pattern from the center out.

For both left and right sides of 265 and 301 Pontiac Engines, the steps involve disconnecting exhaust pipes, removing manifold bolts, and cleaning gasket surfaces. The installation process includes using new gaskets and tightening bolts evenly.

To prepare for exhaust manifold removal:Unplug the oxygen sensor lead.Remove the drive belt and the alternator.

Set the parking brake, block the rear wheels, and raise the front of the vehicle on jackstands. Working beneath the vehicle, remove the two exhaust pipe-to-manifold bolts, applying penetrating oil if needed. Unbolt and remove the exhaust manifold.

Unplug the oxygen sensor and remove the manifold heat shields.

Remove the spark plug wires from the spark plugs, marking them with tape.

1. Disconnect the negative battery cable. 2. Hoist the car and support it firmly with jack stands. 3. Remove the right front wheel for better access. 4. Disconnect the exhaust pipe where it connects to the manifold, using penetrating oil if necessary. 5. Remove the exhaust manifold bolts. 6. Take the manifold out from under the car.

After that, remove the exhaust manifold brace and separate the exhaust pipe flange nuts from the manifold studs, pulling the pipe down slightly to break the seal.

Unbolt the crossover pipe where it joins the rear manifold and remove the exhaust manifold heat shield, noting the difference in bolt retention compared to the front manifold.

To facilitate removal, apply penetrating oil to the threads of all exhaust manifold and exhaust pipe fasteners and allow it to soak in.

For manual transmission cars, detach the front hose from the air pipe, then remove the mounting nuts and take off the front exhaust manifold from the cylinder head.

Install the new manifold in reverse order of removal, ensuring to use a new gasket and tighten the bolts in the correct sequence to the specified torque.