Your car's exhaust system does more than just keep the car quiet; it helps to move emissions away from the engine and the cab of the car, so the engine works more effectively and you aren't breathing in all those pollutants. When there are problems with parts of the exhaust system, this can mean problems for your engine and for the car's overall performance. Note a few symptoms of a damaged exhaust and this can help you to know what to expect by way of repair bills.

1. Engine sputtering; check engine light is on

Your car's engine works with a mixture of fuel and oxygen; sensors in the car note how much of each is needed to keep the engine running optimally. When one of these sensors goes bad, the engine will sputter and even stall from having too much fuel or too much oxygen. Typically the check engine light on your dashboard will alert at the same time. A poor ratio of oxygen and fuel can cause the engine to run hotter than it should, so you might also note if the thermostat reading is above average. If it's not the sensor, it may be that a part of the exhaust has a hole or other damage that is not allowing enough oxygen to be removed from the engine so that the combustion is affected; this is often caused by rust, as noted below.

2. Catalytic converter making noise or breaking down sooner than it should

The catalytic converter is like a filtering system that converts or filters exhaust from the engine and traps pollutants and emission before they can get through the exhaust pipes. When it's overly noisy and breaks down much sooner than its expected lifespan, this often signals oil or antifreeze dripping onto the piece and causing it to rust or otherwise corrode. In turn, it rattles as it tries to work. Have the converter replaced but check the oil pan and the radiator and hoses for leaks or cracks as well.

3. Rattling, noise, and poor gas mileage

Having a bad muffler is not the only reason to hear rattling and noise from your exhaust system. Rust is a common culprit for noise and you can often simply do a visual inspection or run your hand over the pipes, when the car is shut off of course, to note if rust has eaten through any area. When emissions and air pass over these areas, it will cause the exhaust system to vibrate loudly and your engine's performance is compromised, causing sputtering and poor gas mileage. You can cover the parts with muffler tape but it's often best to have rusted parts replaced completely for a permanent fix.