An engine that suddenly drives louder than normal is usually a cause for help. In the majority of cases an underlying issue is causing the engine to rumble. Problems can start from something simple like dirty spark plugs to the more serious failing muffler or catalytic converter.
While some of the problems that can cause a louder than normal engine are easy fixes, many issues are much more extensive and can quickly damage other systems, leading to an expensive repair.
How this system operates:
While a number of different systems can cause a car to run louder, most of the time it is caused in the exhaust system.
The exhaust system is responsible for getting exhaust gases from the cylinder head. This is accomplished through the exhaust manifold, which basically functions as a big funnel diverting exhaust gases away from the engine cylinders. The exhaust gases are let out through a part called the front pipe and from there they travel to the catalytic converter. The catalytic converter gets the harmful elements of the gases such as hydrogen monoxide and carbon monoxide. Finally, the exhaust gases goes out of the catalytic converter into the muffler. The mufflers main duty is to reduce the noise levels of the engine. After the muffler, the exhaust fumes goes out of the vehicle through the tail pipe.
Common reasons why this happens:
- Failing Muffler: Mufflers are always exposed to heat and pressure not to mention road salts, grime and the weather. Over time a muffler will develop rust and develop holes and cracks. Eventually it will begin to fail completely. A vehicle that is running louder than normal is often because of a failing muffler. Other symptoms include a significant drop in gas mileage and an increase in exhaust fumes.
A failing muffler should be fixed or replaced immediately as an exhaust system that is not working properly can lead to additional damage to the engine or catalytic converter.
- Failing Catalytic Converter: The catalytic converter is a key part of the exhaust system and if it is failing the engine will be louder than normal, will go rough and the smell of rotten eggs will be coming from the exhaust. In most situation, a failing catalytic converter will also trigger the Check Engine light. As the converter fails it will no longer be able to burn off the unburned hydrocarbons in the exhaust, or break down the sulfur generated by the engine. This is what produces the strong rotten egg smell. Eventually the vehicle will not run at all as the catalytic converter becomes totally blocked.
- Broken Tail Pipe: The tail pipe gets out of the muffler and exhausts the gases and fumes into the air. A rusted tailpipe will often create holes or will completely fall off at some point. This will increase the noise levels of the car.
- Leak in Exhaust Manifold: The exhaust manifold takes exhaust gases from the engine. If there is a leak in the exhaust manifold it can create the engine to run louder, sputter and run unevenly. In most situation it will also trigger the Check Engine light. A cracked or leaking exhaust manifold can produce bigger problems because of the hot gases that are escaping. They will often melt nearby plastic part. It is also possible for leaking exhaust fumes to find their way into the cabin of the vehicle.
- Worn Seals or Gaskets: The exhaust system has quite a few seals and gaskets and if they are failing it can make the engine to run louder, and sputter at times. Over time, gaskets and seals will wear down and eventually have to be changed. If this problem is not fixed it can end up damaging the exhaust manifold which will be a much more expensive repair.
- Malfunctioning Oxygen Sensors: The job of the oxygen sensors is to measure how rich or lean the exhaust gases are when they exit the combustion chamber. The computer in the vehicle uses this data to adjust the amount of fuel that is entering the engine. A failing or dirty sensor can send incorrect data, resulting in too much or too little fuel going to the engine. This can result in a rough running engine that is louder than normal.
- Bad or Dirty Spark Plugs: Bad spark plugs can make the vehicle to misfire which will make it run louder. Spark plugs give the spark for igniting the fuel in the combustion chamber, if they are not functioning correctly, the fuel is not completely ignited and the vehicle will misfire or sputter. The plugs will need to be chnaged or cleaned.
- Dirty Mass Airflow Sensor: A mass airflow sensor measures the amount of air entering the fuel injection system. This information is sent to the car computer so it can send the correct amount of fuel to the combustion chamber. A dirty airflow sensor can lead to the wrong amount of fuel going to the injectors, which can result in a rough running engine that will sound louder than normal.
How it is done:
A mechanic will check your exhaust manifold, oxygen sensors, catalytic converter, and other important components of your vehicle to determine the source of the loud running engine. The mechanic may need to crank up your vehicle to provide you with an accurate diagnosis.
How important is this repairs?
A failing exhaust system will not only make a car louder it can make it dangerous to drive. Exhaust fumes can make their way into the car cabin, which can present health issue. In addition, minor exhaust issues such as a failing gasket can quickly lead to a more expensive repair like a cracked exhaust manifold or clogged catalytic converter.