Your car's muffler is one of the most vulnerable parts on the car. It's close to the ground, where it gets covered with moisture, mud and dirt. If rust forms and is not stopped, it will corrode the muffler's metal, and the entire exhaust system may have to be replaced, which can be expensive, depending on the vehicle. With a little preventive maintenance though, muffler and exhaust rust can be prevented.
Causes of Rust
Rust occurs on a car or truck muffler when moisture gets trapped on the surface of the metal by mud and dirt or when moisture is allowed to stay on top of the metal where it can eventually corrode the material. In areas with cold, snowy winters, salt is often used on roads to combat ice and snow. If the salt gets on a vehicle's exhaust systems, it can cause corrosion. Many exhaust systems, particularly aftermarket performance exhausts, are made from stainless steel, which is more resistant to rust then regular steel. However, even stainless steel can rust eventually.
Clean and Maintain the Muffler
One way to ward off rust is to regularly clean the muffler with a degreaser or a mild cleaner. Raise the rear of the car so that you have access to the muffler. Rinse off any dirt with a hose and water. Spray on the cleaner if it's in a spray bottle or dip a rag in a bucket of water and wash the muffler. Make sure to clean around the muffler welds and any muffler clamps that hold the exhaust together. Once it's clean, dry it thoroughly with a clean, dry rag. Do this as often as possible to maintain a rust-free exhaust system.
Paint the Muffler
Another way to prevent rust from developing on your muffler and exhaust is to spray paint it. Because of the high temperatures that exhaust systems produce, regular spray paint will not adhere to mufflers when they heat up and will simply burn off. Use high-temperature header or even barbecue paint instead. Jack up the vehicle and place it on jack stands. Tape off anything near the exhaust that you do not want painted. Clean the muffler with soap and water and wipe it down with white spirit. Spray three to four coats of high temperature paint onto the muffler and exhaust system. Make sure any welds in the exhaust also get painted.