Question: Can I recharge my A/C system myself?
Answer: You can if you can get your hands on the correct
type of refrigerant required for your vehicle. But that is now
a major problem for do-it-yourselfers because federal law prohibits
the sale of R12 and R134 automotive refrigerants to "noncertified"
individuals (to become certified, you must pass a written test
approved by the Environmental Protection Agency (EPA) -- something
which all professional A/C technicians must do before they can
legally work on your vehicle). This rule has been in effect since
November 1992.
The law was passed to discourage people from recharging leaky
A/C systems. R12 refrigerant, which is used in all vehicles built
prior to 1993, is an ozone-depleting chemical. So its sale and
use is strictly regulated by the EPA. What's more, production
of R12 ends December 31, 1995. After that date, the only R12
that will be available will be that which has already been stockpiled
or can be recovered and recycled from existing A/C systems. As
the supply dwindles, motorists will be forced to have their A/C
systems converted to the new "ozone-safe" R134a refrigerant
(a job which may require replacing hoses and other parts depending
on the application and model year).
Until late 1994, anyone could still buy refrigerant in large
bulk containers. Because of the high cost of such containers,
the EPA thought few do-it-yourselfers would buy refrigerant in
bulk. But even that loophole has now been plugged. So unless
you're a certified professional technician, you can't buy automotive
refrigerant period.
This law does not, however, make it illegal to own or use
R12 refrigerant. But it does make it very difficult for the average
person to obtain it.
Some companies have responded to the "refrigerant shortage"
by introducing refrigerant substitutes. Unless such a product
is EPA approved, however, it should not be used in your vehicle.
Many of these products are flammable, which could create a potentially
deadly fire hazard if your A/C system were ruptured during an
accident. There is also the problem of "cross-contamination."
Federal law requires professional technicians to recover and
recycle the old refrigerant in your A/C system when doing A/C
repairs. If there's some other kind of refrigerant in your system,
it can contaminate their recovery and recycling equipment.
RECHARGING THE A/C SYSTEM
CAUTION: The high side of the A/C system is under considerable
pressure. If a can of refrigerant is connected to the high side
service fitting, it may explode! The system must therefore be
recharged by using the low side service fitting only. If you
are not sure which fittings are which, do not attempt to recharge
your air conditioner yourself. Wear eye protection and avoid
direct contact with the refrigerant as it can cause frostbite
on bare skin.
The basic recharging procedure goes as follows:
1. Identify the low side service fitting.
2. Determine the type of refrigerant required by the system.
On most 1993 and older vehicles, this would be R12. On most
1994 and newer vehicles, it would be R134a.
CAUTION: R12 and R134a refrigerants are incompatible and
must not be intermixed. Use the type of refrigerant required
for your A/C system only. On most 1993 and newer vehicles, there's
an identification decal or sticker that tells what kind of refrigerant
is required. Also, the size and design of R134a and R12 service
fittings are different to avoid cross-contamination.
3. Connect a can of refrigerant to a gauge set or recharging
hose and valve set. Follow the equipment supplier's directions
for making the connections.
4. Open the valve momentarily on the gauge set or hose to
blow all air out of the line (this is necessary to keep from introducing
air and moisture into your A/C system).
5. Connect the gauge set or hose to the low side A/C service
fitting on the vehicle. This is usually located near the receiver/drier
or accumulator, or suction side of the compressor.
6. CAUTION: Make sure the can of refrigerant is held in
the upright position so only vapor enters the line. Do not tip
the can sideways or upside down as doing so will allow liquid
to enter the low pressure side of the A/C system (This may cause
damage to the A/C compressor). Also, never heat the can to make
it empty faster as doing so may cause the can to explode.
7. Start the engine and turn the A/C system on high. The
compressor should be engaged or cycling on and off (it may be
necessary to jump the compressor clutch directly to the battery
if the system is extremely low on refrigerant to keep it engaged).
Compressor suction will pull refrigerant vapor into the system
and slowly empty the can. This can take up to 10 minutes or more,
so don't be anxious.
8. When the can is empty, disconnect the charging hose from
the service fitting. Use care when disconnecting the "empty"
can from the gauge set or charging hose as it may contain some
residual refrigerant.
9. Add additional cans of refrigerant as needed until the
system is properly charged.
CAUTION: The most common mistake made by do-it-yourselfers
is overcharging. Too much refrigerant can reduce cooling efficiency
just the same as too little refrigerant. To work properly, the
A/C system needs just the right amount. Always refer to the system
capacity specs in a shop manual or other source to determine how
much refrigerant is required. System capacities are specified
in ounces. One can of refrigerant equals about 14 oz. Usually
three to four cans is enough to fully recharge a typical passenger
car A/C system that was empty. If the system is low, one or two
cans of refrigerant are usually all that's required.
