What does the flexi pipe do in an exhaust?
The exhaust flexi pipe is a flexible tube usually made of stainless steel, which is giving the exhaust line enough flexibility during the movement of the vehicle. This helps to limit the cracks that could appear in the exhaust system if the pipe was rigid, or avoid damaging other parts to which it is attached. via
How do you know if your flex pipe is leaking?
Loud noises: One of the first signs of an exhaust leak is a loud noise. If there's a crack in your flex pipe, it will cause an excessively noisy engine. Your pipe might be producing a hissing or tapping sound that can get louder when the generator speed is increased. via
How do you fix a cracked exhaust pipe? (video)