Question: My A/C system is leaking refrigerant.
How can I find the leak?
Answer:The two most common ways for a do-it-yourselfer
to find a leak is to (1) visually inspect the system for telltale
oil stains, or (2) add a can of "leak detector" to the
system and then look for the presence of the colored dye around
hose connections and fittings.
When refrigerant leaks from the system, it immediately evaporates
into thin air leaving no trace except possibly the compressor
oil residue that leaks out with it. Wet oily areas around hose
connections and fittings and/or greasy streaks radiating outward
around the compressor clutch or on the underside of the hood just
above the compressor are good visual clues to where the leak is.
Leak detecting dyes will often reveal tiny leaks that might escape
visual detection. Some are fluorescent and require illumination
with a special light before you can see them. Even so, even dyes
can fail to show you where a leak is if the leak is in the evaporator
(located inside the heater/defroster plenum under the dash) or
in a hard-to-observe or hidden location.
Most professionals use an "electronic" leak detector
that reacts to the presence of refrigerant in air. Such detectors
are extremely sensitive and can detect leaks as small as 1/4 oz.
of refrigerant per year!
FIXING LEAKS
Once a leak has been identified and pinpointed, it should
be fixed. Don't waste your time on "stop leak" products
because they seldom work.
Leaks should be fixed for three reasons. One is because leaks
allow air and moisture to enter your A/C system. Moisture can
react with refrigerant to form corrosive acids and sludge that
can damage the compressor, plug up orifice tubes and/or eat pinholes
in evaporators and condensers. Another is because refrigerant
is expensive. It may seem cheaper to keep recharging your system
with additional refrigerant instead of having the leak fixed,
but in the long run it won't be as the cost of R12 refrigerant
continues to rise. Third, R12 refrigerant is an ozone-depleting
CFC. When it leaks into the atmosphere, it drifts up into the
stratosphere and destroys ozone that protects us from the sun's
harmful ultraviolet radiation.
Before any attempt is made to repair a leak, any refrigerant
that's still in your system should be recovered and recycled.
All service facilities that do A/C work are required by law to
have such equipment.
Once the old refrigerant has been pumped out of your system,
it can be opened for repairs. The desiccant (crystals that
absorb moisture and help protect the system against moisture contamination)
in the accumulator or receiver/drier should also be replaced if
the system has lost all its refrigerant or must be left open for
more than a few hours for repairs.
After the leak has been repaired, the system must be connected
to a vacuum pump to purge it of all air and moisture before it
is recharged with refrigerant. Leaving air and moisture in the
system will greatly reduce the cooling efficiency of the system
and will lead to the formation of damaging acids and sludge.
It's also important to replace any compressor oil that was
lost due to leakage or parts replacement. Use the type and quantity
specified by the vehicle manufacturer.
CAUTION: Using the wrong type of compressor oil or too much
or too little oil may result in compressor failure.
