The first indication of a problem with the air conditioner is that it stops blowing
cold air. The A/C system is meant to be completely sealed, and when problems
arise, it is usually due to gas escaping from the system or contaminants getting
into it.
LEAKS
The compressed gases in the A/C
system require seals and valves,
and over time these will degrade.
Pinholes in metal lines can be a
problem, too. Keep in mind that
a slow leak will eventually turn
into a big one. You can add more
refrigerant to the A/C system,
but the problem will eventually
get worse.
COMPRESSOR FAILURE
Major leaks lead to catastrophic problems, like compressor failures. This can happen when the magnetic
clutch on the compressor fails, which prevents the compressor from spinning, or the clutch fails to release
and the compressor runs all the time.
PRESSURE PROBLEMS
Most issues with the A/C system can
be diagnosed with the use of a set of
gauges. The gauges read the pressure
on both the high- and low-pressure
sides of the
system. Most of the time, checking the
low-pressure side is enough to tell you if
you need professional assistance.
UNPLEASANT ODOR
Since the air conditioning exchanges cold
and hot air, condensation forms on the
condenser located under the dash. This
drips off and runs out of a drain located
at the bottom of the box that holds the
condenser. If the drain becomes clogged,
it creates a cool, moist area for mold and
other unpleasant-smelling things to
grow.
CLOGGED FILTER
Newer cars may have a cabin filter to
clean the air as it passes through the
heater and A/C system. It is usually
located under the dash on the passenger
side or under a panel in the engine
compartment. The filter may become
clogged, causing odor or limited
performance of the A/C and heater
system.