i have a chev s10 pickup 4 cyl. the exhaust is very noisy even though it has a new cat conv and muffler.?

Question

the first shop i went to put a new muffler on. didnt help. the 2nd shop put a new cat/conv on , a little better. do you know where the noise is from?

Answer 1

Start up the truck and crawl underneath and listen and feel until you find it.

Answer 2

See if you have a manifold leak. With the engine cold start up the truck and put your hand around to see if any air coming out. Also, did you check on top of the exhaust pipes for leak too. The muffler places are dumb at times. They just replace the muffler but will not look for leaks,

Answer 3

Maybe one of the clamps holding the system in place is loose, broken, or even overtorqued.
One part of the exhaust system may be vibrating against the chassis or tranny line or whatever.
If I were you, I wouldn't take it to a THIRD muffler shop or you'll be broke. Take it to a regular service garage that doesn't specialize in mufflers.

Answer 4

Look under the truck and you'll see puffs of exhaust smoke coming out from any leaks especially if someone temporarily holds a rag over the tailpipe for 5 seconds or so. Have a friend rev the engine for you, but make sure he puts it in park with the parking brake on and the wheels chocked for safety.

Answer 5

if the noise is a hissing basically, then yes the air filter could be at fault. if the noise is anything else like a vibration or a load pulsing (exhaust noise is what i am trying to describe), then you could have a damaged exhaust manifold, or pipe between the cat and the manifold could have damage to it, there are just so many potential causes for noise. you could have a poor weld on the cat for that matter.

Answer 6

most likely the exhaust manifold or somebody forgot to put a gasket on.

Answer 7

does it have a dough-nut,if so then it might be leaking there.check the clamps.maybe they left one loose.what about the intermediate pipe?is it good,and no holes?