How to find exhaust leaks?

Aug 17, 2005 5 Replies

I suspect my exhaust has a small leak near the manifold. I can't smell much or at all, but I'm hearing some exhaust clatter. The strange thing is, it only happens when the car has been sitting for a few minutes, hot or cold, then goes away after a few minutes of driving.



Car is a 1985 Corolla.



Any help is appreciated! Thanks


Use a piece of fuel hose or similar as a stethoscope and stuff one end carefully into one of your ears and poke around the manifold with the other end listening for the clatter.

Things expand when hot, which frequently seal up small leaks, which explains why it goes away after a few minutes.

Listen thru the other end of a 2-foot piece of rubber hose--vacuum hose ok, or small garden hose; i.e., a stethoscope. HTH, s

Restrict the tailpipe by clamping a hastily-bent piece of sheetmetal or wadded-up shop rag over the end. Don't block it completely, but do block it most of the way. Remove the PCV valve and start the engine. Introduce some light oil into the engine via the PCV valve, and watch your suspected leak point for smoke.

Would things expand and contract significantly in just a minute or two? Even when the engine is hot, and is shut off for a minute or so, the sound will come back.

also check the heat shield - can be rattling if the bolt holes are slightly elongated from wear

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