Nissan Repair: engine sound/ manifold?, replacement job, exhaust manifold

Question
my 1991 Sentra started making a very weird sounds yesterday. all of the sudden it sounded like its no longer a 4 cylinder but rather a V8! I checked under the hood and the sound seems to come from the exhaust manifold. is it possible that something in that area can snap, crack or anything?

Answer
G,

Take the manifold off and replace the gasket.  You probably have a couple of studs that broke off so get a stud and bolt kit for the manifold along with a new gasket before you do the replacement.  These engines usually do not crack the manifold so it should be a gasket/bolt/stud replacement job.