96 lumina exhaust leak ?

[ceasar900]

my 1996 lumina sounds like the muffler is gone when i start it up but once it is warm it sounds fine. i took it to a exhaust shop they said the rear manifold need to be replaced . does this sound correct ? How can i check it to be sure its difficult to get at the rear one.

[dwalmop]

hmmm. never heard of one of those going bad. there are a couple things you should check on your own: make sure it's not leaking where the exhaust manifold connects to the exhaust pipe and: make sure it's not leaking where the manifold connects to the crossover pipe. it's difficult to get back there, but it can be done. if it's leaking up front it should be plenty obvious - it should get louder when you open the hood. if you can get under the car at all it shouldn't be hard to tell where the leak's coming from.

[jeffcoslacker]

Originally Posted by dwalmop

hmmm. never heard of one of those going bad. there are a couple things you should check on your own: make sure it's not leaking where the exhaust manifold connects to the exhaust pipe and: make sure it's not leaking where the manifold connects to the crossover pipe. it's difficult to get back there, but it can be done. if it's leaking up front it should be plenty obvious - it should get louder when you open the hood. if you can get under the car at all it shouldn't be hard to tell where the leak's coming from.

I've seen them crack, and they do act like that. When cold, and the metal is fully contracted, the crack is wide open and they rumble like hell. As it warms up, the manifold expands and the crack closes up. You should check the torque on the studs and donut gaskets before replacing it, true, but they might be right about it. I have not seen one crack on a Chevy engine in recent history either. You may just have incredibly bad luck. Used to be, when they had carbs, I'd just drop a little tranny fluid down the throat and watch where the smoke poured outta to find the leak. Can't do that any more. (not easily, anyway)

[cadgear]

As far as using ATF to find a leak, you could still do it, just use the Accessory vacuum port to meter in a small amount. ATF, seafoam, etc would work. Smokey stuff is always nice to have on hand.

[bstrom1953]

Originally Posted by ceasar900

my 1996 lumina sounds like the muffler is gone when i start it up but once it is warm it sounds fine. i took it to a exhaust shop they said the rear manifold need to be replaced . does this sound correct ? How can i check it to be sure its difficult to get at the rear one.

My car does the exact same thing. Did you ever find out what was wrong?