You will often know when you have an exhaust leak thanks to the loud rasping noise put out by the system.
Unfortunately, as the waste gases from the combustion process tend to be very hot when they come out of the engine this also heats the exhaust up to a level where it is unsafe to touch, preventing you from inspecting the system whilst the engine is running.
However, you can use the following process to find a leak within your exhaust system. You will need a vacuum cleaner with a hose and a piece of pipe with a funnel attachment. You can also find more information from various online sources on the exhaust leak:-
Ensure the engine is off – Before you start on this process always make sure that the engine is off and has had time to fully cool. The exhaust system can retain heat for a good while after the car has been shut down and can burn you on touch.
Connect the vacuum – using the cleaner hose connect the vacuum up to the tailpipe of your exhaust. This is the final part of the exhaust system where the gases leave the car. Turn the vacuum cleaner on so that it is sucking air through the exhaust system.
Use the pipe and funnel – the pipe and funnel acts a little like a doctor’s stethoscope. Use it to listen to the various parts of the exhaust system. You are seeking a hissing sound that indicates a leak, which can be verified by pressing your finger over the trouble area. A sound change confirms that this area is leaking gas.
Keep checking – Once you have found a leak you can always make it temporarily good with a small piece of blue tack or tape. This will then allow you to explore the rest of the system looking for further leaks. Always be sure to remove any temporary measures that you have placed on the exhaust system before running the car again.