Chevrolet 12611641 Manifold, Exhaust

First, unplug the battery negative cable, lift the car with jackstands, and spray penetrating oil onto the catalytic converter connections for the manifold. Unscrew the bolts that keep the catalytic converter on the manifold. Loosen the oxygen sensor cables, then detach the wires from their socket. Carefully unplug the engine wiring cable and move it out of your way. Open the engine covers, then take off the bolts holding the manifold, outer shield, and follow by grabbing the ground wire from the bracket below the manifold. First push the coolant pipe down to reach the lower manifold bolts, then remove the bottom nut holding the pipe while keeping the exhaust manifold attached to the cylinder head. Start with the outside bolts,-working toward the center, remove the bolts to separate the exhaust manifold from the cylinder head, and finally remove the inner heat shields from the old manifold. Use the same steps to unscrew the mounting bolts on the left side manifold, season by season, and disconnect the exhaust manifold from the cylinder head while pulling out the internal heat protectors. Before putting it back together, look for cracks in the manifold. Make sure the bolt threads are still good and clean, then clean all mating surfaces where the parts will connect. Treat inner heat shield bolt threads with an anti-seize compound. Fix the inner shields in place, then put bolts and gaskets onto the manifold. Make sure the retaining tabs connect the assembly tightly during installation. Coat the bolts' threads with a medium thread locking glue 1/4 inch wide, position the manifold on the cylinder head, then tighten the bolts just by hand. For installing the engine manifolds, start in the middle with a torque wrench and work towards the ends. After tightening, push the end of the exhaust manifold gasket down against the cylinder head when necessary. Before screwing in the heat shield bolt, treat each thread with anti-seize compound, then fasten the bolts in place. Undo the steps precisely how you removed them. After that, start the engine to see if it's giving off smoke from any cracks in the exhaust system.

If necessary, bend the exposed end of the exhaust manifold gasket back against the cylinder head.