A leaking exhaust manifold gasket could make a buzzing sound if the leak is big enough, or it could make a ticking sound. You should replace the bad gasket as soon as you notice that it is bad. On some vehicles, the job is relatively easy, but can be difficult on other vehicles, particularly some V-8s that are a tight fit in the engine compartment. Though the bolts might be difficult to access, in most vehicles, you are able to pull the manifold away from the engine far enough to insert the new gasket.
Remove the bolts or nuts on the exhaust manifolds, using the appropriate socket. If a socket will not fit -- it won't on certain vehicles where the bolt is too close to the pipe, especially on headers -- use the appropriate wrench to remove the bolts.
Pull the exhaust manifold gasket out from between the manifold and engine. Be sure that no gasket pieces fall into the manifold. If the gasket sticks to the manifold or the head, scrape it off with the scraper.
Slide the new gasket into place. If the vehicle uses nuts, it will have studs on the heads. Fit the bolt holes on the gasket over the studs and slide the gasket up against the head. If you removed bolts, match the gasket to the manifold, then insert a screwdriver into the manifold and through the gasket on each end, to help hold the gasket in place.
Position the manifold against the head and push the screwdrivers into the bolt holes on the head. While holding the manifold in place, insert a bolt into one of the empty holes and tighten it as far as you can by hand. Insert a second bolt and tighten it. Remove the screwdrivers. If you are working on a vehicle with studs, position the manifold on the studs against the head. Install the nuts and tighten them firmly.
Install the rest of the bolts on a manifold that uses bolts. Tighten them all by hand as far as you can. Firmly tighten the bolts with the appropriate socket or wrench.
