The exhaust system is an important part of your vehicle, because it expels burnt engine gases from the car. The exhaust also controls emissions of your vehicle, and any damage or leaks to it can affect the performance of the car. Poisonous carbon monoxide can seep into the passenger area, which is why it is important to diagnose and repair exhaust leaks right away.
Physical Damage and Leaks
Perform a visual examination of the vehicle and its exhaust system for signs of physical damage or scrapes. Look for signs of black soot on the exhaust and tailpipe, which is a sign that there is carbon built up from a leak.
Scraping the bottom of the car while driving over a curb or speed bump is a common way to cause damage to the exhaust. Holes and scrapes can cause the exhaust to start leaking.
The oxygen sensor is in the exhaust system, and scraping the bottom of the vehicle can damage the oxygen sensor, which will cause exhaust leaks.
Check your vehicle's undercarriage for signs of rust. Older vehicles are vulnerable to rusting, and rust will eat metal, causing leaks in the exhaust pipe.
Welded joints are common spots for exhaust leaks. Check all joints on the exhaust and make sure there is no rust or damage.
Shaking and Noise
Vehicles with an exhaust leak will shake and rattle while idling at a red light. A different noise, such as a ticking or popping, is a common sign of an exhaust leak. A loud roaring noise that is different from the usual sounds your car makes is also a sign of an exhaust leak problem.
Have a friend gently accelerate the engine while you have the hood up and are listening outside the vehicle. Listen for a deep, throaty sound or loud sputtering that sounds different from what you are used to hearing from the car.
Smelling a gas while your car's windows are rolled up is a sign of an exhaust leak. This sign is often easier to notice in colder months when you drive with the windows up and the vents are opened for hot air. The odour may not be noticeable while you are outside the vehicle but is always present as you are driving.