GM 12672961 Exhaust Manifold

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In order to get to the exhaust manifold, it is necessary to disconnect the wire from the negative terminal of the battery. Disconnect the crossover exhaust pipe which joins the two exhaust manifold but do not remove the pipe from the car to save you time during reassembling. In the front manifold, one has to disconnect the EGR tube from the EGR valve and the exhaust manifold. As to the rear manifold, one must first unplug the wiring harness of the oxygen sensor and then lift up the car and put it on the jack stands. Remove the exhaust manifold/Catalytic converter connection and position the exhaust pipe off the manifold. Next, if the manifold heat cover is in the way unscrew it, and then unscrew the manifold mounting bolts and O-ring and finally remove the exhaust manifold and O-rings used in joining it. For installation, first, remove the old gasket material from the mating surfaces and then check the manifold for warpage and cracks, the later with a straight-edge. Even if the thickest of the feeler gauge that you are able to insert between the straightedge and flange surface is 0.030 inch, then it will be the warrant of the manifold to be taken to an automotive machine shop for resurfacing. With a new gasket, put the manifold to the extent of the head and use the bolts, nuts to fix it; tighten the nuts moderately from the centre and from outside to a specific torque. Last of all replace the other components in reverse order and crank the engine to feel for exhaust gasket blowby between the manifold and cylinder head as well as the manifold and the exhaust pipe.

To get rid of the exhaust manifold in the 3.0L engine, and 2013 and newer 3.6L engines, unbend the cable on the negative terminal of the battery and then safely lift the car on jack stands. Now make use of penetrating oil on the studs and nuts holding the catalytic converters to the exhaust manifolds, then remove the bolts holding the converters and disconnect them. For left manifold, unscrew oil dipstick tube; for right manifold, undo air filter inlet and remove brake fluid level sensor connector. Thirdly, we need to remove both torque strut mounts and brackets, of course, and the oxygen sensor electrical connectors, as well as the wiring harness clip. Unbolt the exhaust manifold heat shield and the heat shield itself, then unbolt the exhaust manifold bolts, though the lower bolts to the right manifold are installed from under the vehicle. Remove the exhaust manifolds and overhaul the gaskets as it is not necessary to re-use them. Inspection of several points should be done before engine installation, these include; the cracks on the manifold, the condition of the bolt threads for the manifold and the condition of the manifold and cyilnder head mating surfaces. Depressurize the cylinders and scrape the block and head surfaces with a gasket scraper applying special care not to scratch the aluminum materials. If any manifold bolts are broken should take the manifold to cylinder head reconditioning shop to have it machined for good sealing. Position the manifold over the cylinder head and fit the nuts of the mounting bolts loosely and then, using a torque wrench, tighten the bolts from the center outwards. If so, one has to form the protruding end of the exhaust manifold gasket on the cylinder head. Coat the threads of the outer heat shield bolts with anti-seize compound, then install and torque to the recommended value, then perform the procedure in the reverse of the removal process specified above. Lastly, turn on the engine then it is time to check for exhaust leaks.

Remove the exhaust manifold heat shield fasteners and the shield.

Soak the retaining nuts with penetrating oil and remove them from above.

Unbolt the crossover exhaust pipe that connects the two exhaust manifolds, ensuring it does not need to be completely removed from the vehicle.

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