The exhaust system is located under the car, which makes it susceptible to
damage from harsh driving conditions. The two biggest problems with the
exhaust system are leaks, which can cause loud noise while the engine is
running, and emission failures in the catalytic converter or oxygen sensors.
EXHAUST MANIFOLD LEAKS AND
WARPING
Exhaust manifolds can crack or warp,
and the bolts holding them can loosen,
causing an exhaust leak right next to the
engine.
Depending on the size of the leak, it may
sound like a small tap, tap, tap, or a loud
rumble while the engine is running.
Leaks at the manifold will usually cause
a black stain from the escaping exhaust
gas.
GASKET LEAKS
A gasket is a seal that fills the space at the
connection point between two
components, such as two pipes in the
exhaust system.
Hot gases can burn away the gaskets
and cause leaks. Gasket and pipe leaks
result in louder than normal sounds
from the
exhaust system when the engine is
running.
CLOGGED OR POISONED CATALYTIC CONVERTER
Excessive oil or carbon can clog a catalytic converter. When this happens, the engine will not accelerate
very well and may stall after a few minutes. An engine with a clogged converter may also send an error
code from the O2 sensors to the computer. A clogged converter should be replaced by a professional.
Catalytic converters can also become “poisoned,” usually due to an additive run in the engine. These
additives coat the converter and cause it to stop working or work less efficiently. Poisoned converters can
be detected by the O2 sensor or by an emissions test.
O2 SENSOR FAILURE
The oxygen sensors measure the output from the engine and tell the computer how to adjust the fuel and
air mixture for the most efficient operation. If something is wrong with the O2 sensor, the “check engine”
light will come on, and the computer will post an error code.
leak
EXHAUST LEAKS
Punctured or rusted-out exhaust
components can cause leaks.
Leaks make the engine noise
louder and can be dangerous as
they can allow toxic gases into the
cabin.
BROKEN HANGERS
The flexible part of the hanger can
fail, causing the exhaust system to
sag or even break. When a hanger
breaks, you may hear a “clunk” as
you are driving due to the exhaust
system hitting the car, or it can
start dragging on the ground. A broken or damaged
hanger should be replaced.
