Your car's exhaust system is designed to remove noxious gases formed during combustion from the engine in order to keep things running smoothly and help prevent the motor from overheating or misfiring. This system is also designed to minimize engine noise with the use of a muffler, and the catalytic converter is in place to reduce emissions. Different warning signs point to issues with the various parts, and leaks are the most likely issues you will encounter with your car's exhaust system.
When parts of the system begin to wear down, it is not uncommon for leaks to spring up. They can occur anywhere along the system, which runs from the cylinder head all the way to the tailpipe. Leaks can result in increased emissions and when the hot gases are leaving the exhaust system underneath the car, they can damage other parts.
Signs of exhaust leaks
There are a number of sounds associated with exhaust leaks that you will hear when driving your car. You may hear a rattling noise, popping, clicking or even loud roaring sounds if the exhaust system has a leak. The roar will stand out from the typical growl of an engine. Other sensations may be indicative of this issue as well. Vibrations when idling and the scent of gasoline or other fumes can also point to an issue with the exhaust system.
Inspecting the exhaust system for leaks
Start the car and check for leaks before the car warms up, as the pipe heats up quickly. Then, listen closely for sounds of hissing or popping along the length of the car. Have an assistant cover the end of the tailpipe with a rag. This will force the exhaust gases to exit through any leaks, which should increase the volume of any sounds you may have heard. Carefully run your hand along the exhaust pipe to feel for any air being blown out of leaks. but be sure not to actually touch the metal. If you can get underneath the car, you can visually inspect the exhaust system for signs of damage, which typically occurs where the pipe is connected to other parts - the cylinder head, the muffler and the catalytic converter.
Troubleshooting the pipes
Since the exhaust system is constantly being exposed to high temperatures, this can damage and degrade the metal pipes over time. This may lead to the pipes rotting or weakening, which can cause to leaks and other issues. Make sure the car has been off for a while so it has had time to cool down. The exhaust pipes can get very hot and may take longer than the rest of the car to reach a touchable temperature. Take a pair of pliers and insert them into the end of the tailpipe. When you open them up, you should feel resistance from the pipe. If it gives at all, you'll need to replace the pipe. It is also wise to thoroughly investigate any rust patches to determine how extensively they have penetrated the metal.
Some leaks can be repaired if they are small. However, leaks are typically created due to rust and general wear, and welding or a patch will only be temporary. Once the exhaust system starts to show signs of wear, you'll likely need to replace it. This will also help prevent further leaks from forming. If the metal on the exhaust system begins to wear down, the formation of a few small leaks will likely point to more issues down the road.