The exhaust manifold is attached to the cylinder head and carries each cylinders exhaust and combines it into one pipe. The manifold can be produced of steel, aluminum, stainless steel, or more regularly cast iron.
Every modern fuel injected cars use an oxygen sensor to calculate how much oxygen is present in the exhaust. From this the computer can increase or subtract fuel to obtain the correct mixture for maximum fuel mileage. The oxygen sensor is planted on the exhaust manifold or close to it in the exhaust pipe
This muffler-like part changes harmful carbon monoxide and hydrocarbons to water vapor and carbon dioxide. Some converters also reduce harmful nitrogen oxides. The converter is found between the exhaust manifold and the muffler.
Mufflers serve to keep the exhaust quiet to acceptable levels. Bear in mind that the combustion process is a series of explosions that produces allot of noise. Most mufflers use baffles to bounce the exhaust around sending off the energy and quieting the noise. Some mufflers also use fiberglass packing that absorbs the sound energy as the gases flow through.
In the center of all the aforementioned parts is the exhaust pipe which conveys the gas through it’s journey out to your tail pipe. Exhaust tubing is usually produced of steel but can be stainless steel (because of its ability to lasts longer due to it’s corrosion resistance) or aluminized steel tubing. Aluminized steel have better corrosion resistance than plain steel but not better than stainless steel. It is however cheaper than stainless steel
Common Exhaust Issues
First, the worst enemy of your exhaust system is corrosion…. or more often known as rust. Rust is created by moisture reacting with the iron in the steel and forming iron oxide. Moisture or water vapor is found in the exhaust as a by-product of combustion and the catalytic converter. Moisture can also come from the outside in the form of rain. Short trips in your car can shorten the life of your exhaust system. When you turn off your engine whatever water vapor is in the pipes condenses and turns back into a liquid. On a short trip the water never has a chance to get hot enough to turn back into water vapor and just stays in the system and rusts away the pipes. If you drive for short periods consider replacing your exhaust system with stainless steel when the plain steel one rusts through. If you drive more than 15 miles at a time then you should not have to worry about this. However If you live in an area that uses salt on the roads in the winter time, be sure to wash the underside of your car with water every few weeks. Salt increases the corrosion process thus removing it as soon as possible will help stop the rust. Make sure you run the engine after washing to drive off all of the water on the pipes.
Noticed a decrease in your gas mileage? Your oxygen sensor may be wearing out. As time goes on the oxygen sensor begins to wear out and becomes less accurate. This oftentimes results in a much fuel mixture where your car engine burns more fuel than should be needed. often times your check engine light will come on to alert you to a failing oxygen sensor. A suggestion of changing the oxygen sensor every 60,000 miles just to be safe. Even if your check engine light does not come on, you could be using more gas than you should.
Next part in line to wear out is the muffler. Most of the time mufflers rust through and need a replacement. There are many options available for replacement of mufflers. Some cheap and others expensive. However if you plan on keeping your car for a longer period of time, spending an extra cash and get an OEM muffler or a high quality name brand muffler might not be a bad option.
On some instances, the catalytic converter becomes clogged and need to be replaced. Symptoms include loss of power, heat coming from the floor of your car, glowing red converter or a sulfur smell. Never let a mechanic tell you that you can do without the catalytic converter. Removing this component is illegal in most states and can lead to a hefty fine to the government if you are not careful.