Automotive Air-Conditioners
Unfortunately, this page will not provide you with new or novel alternatives designed to make your driving experience more comfortable during the heat of summer. However, there are some tips you should learn to make maintenance of your automotive air-conditioning system less expensive and troublesome.
Home appliances, such as freezers, refrigerators, and air-conditioners, are relatively trouble free because the cooling loop, the compressor, evaporator, and condenser, are hermetically sealed during manufacture, meaning leaks are rare until they have been serviced by a technician who has opened the system.
Auto-motive air-conditioners are subject to much vibration and stress during normal operation of an automobile. The compressor, evaporator, and condenser must be connected by flexible couplings with several seals of synthetic material. During periods of non-operation, such as fall and winter, the seals are not being lubricated by circulation of the refrigerant gas and refrigerant oil. Seals can dry out, allowing escape of the refrigerant gas.
Some older vehicles may still use the R-12 refrigerant system. Because of possible concerns for damage to the ozone layer, R-12 has been phased out and replaced with R-134. Servicing an R-12 system may cost as much as $300 because of the heavy taxes levied upon use of R-12. The first thing a car owner should do is have the unit retro-fitted for use of the much cheaper and environmentally friendly R-134 refrigerant. Be prepared to pay a lot, perhaps more than an older vehicle is worth, if you take the car to a dealer. An honest, and competent garage, should be able to retrofit your system for around $300, perhaps less!
Although I have no supporting data, I suspect the R-134 molecule is much smaller and slipperier than the R-12 molecule, meaning small leaks which may not have been a factor when using R-12 will allow R-134 to escape much quicker, and require recharging more frequently until the leaks have been attended to.
You can save some expense by operating your air-conditioning unit for about 10 minutes each week, simply to circulate the refrigerant gas and lubricating oils within the system, reducing the rate at which seals may begin to dry and leak. It may sound silly to turn your air-conditioning on HI during the winter, but at the present cost for refrigerant gases, you may save $50 to $60 by the time summer rolls around.
The biggest money saving tip is to service and recharge your system yourself. Fortunately, "do-it-yourself" kits exist and can be purchased at many automotive or home improvement centers. R-134 refrigerant gas is sold in 14 oz. containers between $6 and $9 each. Recharging kits, with the needed hoses and attaching fittings, sell between $15 and $25.
I feel it is more cost effective to spend up to $20 for a can of sealant, and then purchase the needed refrigerant separately, instead of spending $9 to $12 for a 14 oz. can of refrigerant containing 3 oz. of sealant. What you spend for the more expensive (and effective) sealant, you will save on the cost of refrigerant without sealant.
Recharging your system is not difficult, simply follow the label instructions provided with the recharging kit. Refrigerant should ALWAYS be added to the LO-side of the air-conditioning system, not the HI-side. Refrigerant gases are compressed in the compressor, which is the heart of your system. From the compressor, liquid refrigerant under high pressure flows to the condenser (usually in front of your radiator) where heat is removed by circulation of ambient air.
From the condenser, the liquid gas flows to the evaporator, usually through a small aluminum colored container called an "accumulator/drier." Access to the LO-side of the refrigerant system is located at or near the drier, and is identified by tubing 3/8 to 1/2 inch in diameter, instead of smaller tubing used for the condenser. Access to the HI-side is not always provided since it is used only by factory trained service personnel. ONLY AFTER you have identified the HI and LO side access points to your system, are you ready to begin the charging procedure.
With the engine running and air-conditioning turned on HI.
Attach the recharging hose to the can of refrigerant gas. Take care not to damage the soft aluminum threads.
Attach the other end of the recharging hose to the bayonet fitting of the LO-side access point.
Turn the T-handle of the recharging hose all the way clockwise to puncture the seal on the can of refrigerant gas.
Turn the T-handle 7 to 10 turns counter-clockwise allowing vapor to flow into the system.
The can of refrigerant gas should quickly become cold on the bottom, if not, open the valve further.
The can will begin to warm when all refrigerant has been added to the system.
Check the output of the air-conditioner. Continue adding refrigerant until the discharge is cool (about 50-60°).
The capacity and type of refrigerant for your system is usually given in your owner's manual, or on a data plate affixed inside the engine compartment. A system requiring 4 lb, 8 oz, (72 oz total) may need five to six cans of refrigerant if totally empty. Don't forget to include the ounces of sealant you add when purchasing refrigerant. Unused cans can safely be stored in your home freezer until the next time you need to recharge your system. (Cans stored in very cold conditions have a low internal pressure which reduces the probability of leaking.) Unused cans should not be stored in the trunk of your vehicle where they will be subject to a high temperature environment.
If your system requires recharging every 2 to 4 weeks, you have a very serious leak which needs the attention of a trained technician at your dealer or garage.