How to Tell If a Car Has an Exhaust Leak

CARS.COM — Your ears and nose can alert you to some exhaust leaks, but they may not be able to detect all leaks, including ones that could allow carbon monoxide inside your vehicle, which can be hazardous to your health. A hands-on inspection at a repair shop is the best way to determine if you have a leaky exhaust.

A loud, or hissing, exhaust is a good indicator of leaks, but noise from the engine, your tires or from your surroundings while you're driving may cover up the exhaust noise. Likewise, though you can smell gasoline and some exhaust aromas, carbon monoxide is an odorless and colorless byproduct of combustion, and it is potentially fatal.

Symptoms caused by carbon monoxide after more than a few minutes of exposure include headaches, dizziness, drowsiness and nausea.

Exhaust systems last years longer now than they did before the 1990s, when most manufacturers began using aluminized steel or stainless-steel parts that are more resistant to corrosion. Even so, exhaust systems can rust, and that can happen sooner on vehicles that are frequently driven short distances. Short trips don't allow the exhaust system to get hot, and water vapor generated during combustion remains in the muffler and other exhaust system parts, accelerating corrosion.

Corrosion produces more than gaping holes that are obvious to see. Pinholes that make little noise can form in places that are hard to see, such as on the top side of an exhaust pipe, muffler or catalytic converter. Even if the pipes and muffler are in good shape, the connections between components can rust or come loose from driving on rough roads; sometimes gaskets wear out. Leaks can also occur under the hood, where the exhaust manifold attaches to the engine at the upstream portion of the exhaust system.

On vehicles that are more than 5 years old, it is a good idea to have a thorough inspection of the exhaust system every year or two to check for leaks and other damage. Even if no leaks are found, the inspection may uncover loose parts or minor damage that can be repaired before it becomes major (and costly) damage.