In order for your BMW 3 Series to run, air and fuel must burn in the combustion chamber. This process produces at least six different emissions, including the dangerous gases nitrogen monoxide, nitrogen oxide and carbon monoxide. The exhaust system removes these emissions from your vehicle, allowing to be safe not only for passengers and the driver but the environment as well. Other important functions of the exhaust system include ensuring your BMW 3 Series is running with the most fuel efficiency and quieting the loud explosive noises of the combustion process.
What are Exhaust Parts?
Your BMW 3 Series exhaust system features a series of pipes and chambers that starts at the engine and ends at the tailpipe at the back of your car. Although most vehicles have only one exhaust system, some cars with eight-cylinder engines may have two--one for the left cylinder and one for the right. A typical exhaust system consists of five main parts.
As its name suggests, the muffler is usually connected to the tailpipe of a car and is responsible for silencing the very loud noises of the combustion process that happens throughout the exhaust system. The muffler is a metal box that contains a series of tubes called baffles, some with holes in them. As the combustion sound waves travel through these pipes, they lose energy along the way and become quieter. The resonator is located at the back of the muffler and cancels out the sound waves through built-up pressure. Some types of mufflers absorb the sound waves via fiberglass, and the most effective mufflers use both methods. If you change your BMW 3 Series muffler, you’ll give your exhaust system a completely different sound.
The exhaust manifold is attached to the engine at the cylinder head and is responsible for venting the exhaust gases generated by multiple cylinders into one single pipe. The manifold also works to burn any leftover fuel that the engine doesn’t properly burn.
The catalytic converter is the next step of the process and is responsible for converting the harmful hydrocarbon and carbon monoxide gases into water vapor and carbon dioxide, making the exhaust safer for the environment. Although your Series 3 will run without a catalytic converter, most states require all cars to be equipped with one.
The oxygen sensor is located in or near the exhaust manifold and is responsible for sending oxygen level readings to your vehicle’s computer. Armed with this information, the computer then regulates exactly how much fuel the engine needs to obtain the best possible fuel efficiency.
The exhaust pipes begin at the manifold and end at the tailpipe. The exhaust makes its way from the manifold through these pipes where it makes its final exit outside of the car.
Potential Problems with Your Exhaust Parts
One of the biggest issues your exhaust may face is that of rust. When your exhaust parts begin to rust, there’s a greater chance that they may break or crack and thus cause an exhaust leak. Living in an area in which salt is used on the roads may increase the risk of rust since salt causes corrosion, but most Texans needn’t worry about snow- and salt-covered roads unless you’re living in El Paso or the Texas Panhandle. Still, hosing down the bottom of your car every few weeks in the colder winter months can help to reduce the likelihood of corrosion, but make sure you don’t overdo it as leaving excess water on your Series 3 can also lead to rust.
Additionally, if you drive in a lot of stop-and-go traffic or if your trips consist of 15 miles or less, you may also be at a greater risk of exhaust problems. Once your car stops, the water vapor in the system condenses into water, and if the car is only running for a few minutes, the pipes can’t heat up enough to evaporate this water. In turn, the condensed water can turn to rust. You may also face an exhaust system leak if the parts crack or become damaged due to normal wear-and-tear.
Signs You Have an Exhaust Problem
If you notice fumes coming from your car that have an odor, it might be a sign that your exhaust is leaking. If this happens, roll down your windows to minimize the fumes you inhale. Also, popping or hissing noises coming from your BMW Series 3 may be an indicator of a muffler that requires replacement or a leak somewhere in the system.
You can also identify other problems with a visual check. Examine your exhaust from engine to tailpipe and make note of any holes or cracks, particularly where one section meets the next such as the joins and seams between the cylinder and the exhaust manifold. Keep in mind that even surface rust, though seemingly not serious, can quickly turn dangerous if the part is rusted from the inside or rusted through completely. Even if there are no signs of trouble, you may consider having a mechanic check out your car when you’re in for a routine oil change or other minor repairs.
Additionally, a buzzing or rattling noise might indicate that a heat shield around the catalytic converter or exhaust pipes is loose. If you’ve been experiencing decreased fuel efficiency, you may have a plugged catalytic converter or a malfunctioning oxygen sensor. Remember that there may be a leak you can’t see or smell since carbon monoxide doesn’t have an odor, and it goes without saying that catching a leak or other exhaust problem early on can greatly reduce the amount of money you spend on repairs down the road. Since the exhaust system is such a critical part of your vehicle’s safety and function, it’s important to keep your eyes open and be aware of any odd sounds or smells that may be coming from the car and have it checked as soon as possible at the first sign of trouble.