Checking exhaust system for leaks

toolmanmike said

The most un-scientific way is to stuff a potato up the pipe. Don't laugh, it works. Just cut it out with a knife.

Click to expand...

This is the way to blow a big hole in a weak muffler,, ask me how I know..

As mentioned , a friend holding a cloth over the exhaust, preferably with a glove,, cuz it'll get hot,, and just hold as much pressure as poss,, then you move along the pipe,, any leaks will be quite evident..

This is Standard muffler shop technique

hope it helps