jamesbfishin

Had a valve lash adjustment done about a month ago as well as a leaking cp3 replaced. Since that time I've noticed a strange sound that seems like its coming from the exhaust system. Sounds like someone is hitting the exhaust with a hammer, loud ping. It'll happen while I'm driving, and when I shut the truck down, thought it might have been the pipes moving as they cool but I can hear it while Im driving even after the truck has been running for an hr. any thoughts

Jeff in TD

I guess I'd crawl under it when it is cool and look at the exhaust hangers and give the whole truck a good eyeballing, shaking and pushing on everything.

If that doesn't help, maybe when it is making the noise on cool down you could crawl around and isolate where it is coming from.

mq105

It happens only while running, or also when the engine is off?

jamesbfishin

Happens while running and after I park and shut down, been under the hood to listen, shook every pipe and joint, checked all hangers, everything looks fine. No movement, everything is tight. Very strange, much louder than normal movement from cooling after shutdown.

Hard to tell where its coming from, under the hood sounds like down pipe or exhaust man, from under the truck sounds like the entire system

Adaminak

One of the baffles in your muffler or the cat insert broke free somewhere and contracting at a different rate than the surrounding metal?

jamesbfishin

Has to be the cat then, muffler is gone. If Im running down a highway for an hour and there is a consistant temp running through the exhaust will a broken baffle or insert cause the hammer sound when there really shouldnt be that much expansion or contraction?

mq105

If you hear the sound when the truck is not running, then it has to be an expansion/contraction issue, right? There is no mechanical movement when the truck is off. Exhaust manifold crack/leak?

jamesbfishin

That's the strange part about it, it does it after shut down and while I'm driving.....