Your car's exhaust system carries away the gases created when the
fuel and air are burned in the combustion chamber. These gases
are harmful to humans and our environment. A frequent check of
your exhaust system is a must to provide for you and your
family's safety. Make sure there are no holes in the exhaust
system or in the passenger compartment where exhaust fumes could
enter. Let's begin by listing the parts of the exhaust system and
their functions.

Exhaust manifold: The exhaust manifold attaches to the cylinder
head and takes each cylinders exhaust and combines it into one
pipe. The manifold can be made of steel, aluminum, stainless
steel, or more commonly cast iron.

Oxygen sensor: All modern fuel injected cars utilize an oxygen
sensor to measure how much oxygen is present in the exhaust. From
this the computer can add or subtract fuel to obtain the correct
mixture for maximum fuel economy. The oxygen sensor is mounted in
the exhaust manifold or close to it in the exhaust pipe.

Catalytic converter: This muffler like part converts harmful
carbon monoxide and hydrocarbons to water vapor and carbon
dioxide. Some converters also reduce harmful nitrogen oxides. The
converter is mounted between the exhaust manifold and the
muffler.

Muffler: The muffler serves to quiet the exhaust down to
acceptable levels. Remember that the combustion process is a
series of explosions that create allot of noise. Most mufflers
use baffles to bounce the exhaust around dissipating the energy
and quieting the noise. Some mufflers also use fiberglass
packing, which absorbs the sound energy as the gases flow
through.

Exhaust pipe: Between all of the above mention parts is the
exhaust pipe which carries the gas through it's journey out your
tail pipe. Exhaust tubing is usually made of steel but can be
stainless steel (which lasts longer due to it's corrosion
resistance) or aluminized steel tubing. Aluminized steel has
better corrosion resistance than plain steel but not better than
stainless steel. It is however cheaper than stainless steel.

Common Problems:

Well the worst enemy of your exhaust system is corrosion.... or
more commonly known as rust. Rust is caused by moisture reacting
with the iron in the steel and forming iron oxide. Moisture, or
water vapor is present 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 shut down 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 distances 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.

If you live in an area, which uses salt on the roads in the
wintertime, make sure to wash the underside of you car with water
every few weeks. Salt speeds up the corrosion process and getting
it off as soon as possible will help stop the corrosion. Make
sure you run the engine after washing to drive off all of the
water on the pipes.

Noticing a decrease in your gas mileage? Your oxygen sensor could
be going south on you. As time goes on the oxygen sensor begins
to wear out and becomes less accurate. This sometimes results in
a rich fuel mixture where your engine burns more fuel than is
needed. Most of the time your check engine light will come on and
alert you to a failing oxygen sensor. I suggest changing the
oxygen sensor every 60,000 miles just to be safe. Even though
your check engine light might not be on, you could be using more
gas than is needed. Pay a few bucks and change the sensor, your
wallet will thank you when you have to buy less gas down the
road.

The next part in line to go is the muffler. Most of the time
mufflers rust through and need to be replaced. There are allot of
options out there for replacement mufflers. Some cheap and some
expensive. It holds true... you get what you pay for. If you plan
on keeping your car for any period of time, spend the extra cash
and get an OEM muffler or a high quality name brand muffler.

On rare occasions the catalytic converter will become 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.

That's about it for the exhaust system; just remember that rust
is the biggest enemy to your exhaust system. Take the
above-mentioned steps and your exhaust system will last a long
time.