I think....

[Lou]

I've got a hole in my exhaust. How can i be sure i do actually have one without going to the garage?

 

[TheCake]

Well if it was leaking you feel it, so with your engine running, run your hands down your exhaust - not TOUCHING as it will be hot, but close enough so you can feel all the parts of the exhaust. If its blowing thanks to a hole - you'll feel air escaping.