air conditioner recharge???????

guzzi

I have a 1992 Madza Miata. The air conditioner isn't cooling like it did when I bought it a 1 1/2 years ago. I have 3 cans of R-12 (14 ounce cans) and the adaptor to put it into the system, but the adaptor does not have a pressure gauge on it.
What do I need to do to recharge my system???

                          Thanks, Joe

swschrad

load your stuff into the trunk, go to a reputable EPA-licensed a/c mechanic, have him run tests on the system, and sell/trade/have him use if needed your cans of R12.

there are federal laws now against working with R12 systems unless you have tested in and have freon recovery equipment. no venting into the atmosphere. that means no wild refilling is the rule of law, leaks need to be fixed.

it is most likely if you have a leak that you will be encouraged to convert to R134a by the shop... or by the price tag... after repairs are done and the system is evacuated and ready for a reload.

Mr_Shiftright

Yeah, R12 is nasty stuff to be releasing into the air. Be a good citizen and convert over to R134 or have a qualified shop do your R12. The Wild West is dead for R12.

 I've done this conversion (some time ago) and now it's much cheaper and more convenient for me to service my A/C, so it all works out eventually over the long run.

isellhondas

It'll never get as cold as the old R12. It's O.K. but not quite the same.

Don't try to fill it yourself. A face full of R12 can blind you.

swschrad

and some are worse. there's a federal law against using anhydrous ammonia for home cooling, because of enough families choked in their sleep in the 20s when fridges leaked. you can use it in trailer fridges, because there is so little, and it vents to the outside in those systems, so they get nice and cold on one little gas pilot light providing the energy. once it conks out, however, nobody will repair them.

for that matter, if you screw up and connect to the high side of a car system under operating pressure, the leakage stream can freeze and wreck your hand(s.) a turbine commercial cooling unit might not have the delta-pressure, but the amount of refrigerant that would get you negates the supposed advantage.

that's one reason you should always review a potential repair before digging in... lots of hazards and places for, uh, detrimental outcomes whenever you deal with a system using lots of energy. don't figure on duct tape holding chassis springs in place, use logging chain... and don't figure that escaping refrigerant is only pollution. it's also lifetime SSI disability payments for the unprepared. I'm finishing rehab of an old but grand ham radio that has beryllium oxide blocks insulating 1500 volts from the outside case... two suddenly-deadly hazards for the price of one... and fortunately for the "Darwin factor," they are identified and easily prepared for.

q45man

When R12 leaks out air moisture is forced in by atmospheric pressure. This moisture combines with the residual oil and turns into ACID which eats the aluminum from the inside. Vacuum the system down, repressurize, check and find leaks, repair the leaks, replace the receiver dryer and recharge.

If you haven't waited too long internal dmage may be at minimum.

Conversions to R134a are always less successful as the 4F warmer outlet temperature is the equivalent of a 20% less effective AC system.

Mr_Shiftright

Yeah, but you know, in "real life" most AC systems today are just great. Maybe my R134 conversion wouldn't be great in 105 degree heat in Phoenix but this is a climate extreme. At 95 degrees it is just fine after 5 minutes of operation. The idea is to "keep cool", not preserve sides of beef in your car, right?

badgerfan

I had conversion done on my '90 Taurus when it was about 7 years old. Converted system worked fine and I really didn't notice much deterioration in performance. I don't know how it would do in the desert southwest, but it worked fine on summer 90 degree plus days in my location.

swschrad

I stepped on the gas smartly pulling out from a newly-green traffic light, and in the 97 degree heat and high humidity, I was getting hot air for a couple minutes. first time I've felt it, but I've expected it. because modern cars, back to when they started making FWD with 4-bangers in this country, load-shed the a/c on acceleration to avoid lugging the engine down if you're trying to get out of a big truck's way, for instance. my ford will even load-shed the alternator if it thinks it has to, depending on what you are doing with the right foot.

and with R134a systems having less power than R12 units, it takes a minute or so to get the evaporator cool again once the engine computer lets the a/c clutch back in again.

not the end of the world. and if you know how things work, you realize that it's not an a/c intermittent failure.

if this is news to any friendly readers out there, use a lighter foot or lock out overdrive and see if you get cooler on those nasty hot days. it just might work.

0patience

swschrad,
It is sometimes called a WOT cutout switch.

swschrad

WOT = Wide Open Throttle.

isellhondas

We used to cool down choke springs by shooting them with R-12!

Worked great too!

swschrad

working maintenance who would use R11 or R12 spray from the 12-1/2 pound tanks to cool individual cans of pop. one night, one of 'em wondered what would happen to the tubes of our sound system if he cooled it down with R11.

shattered 'em, and we had to scrap the thing.

that's presumably in the training book for the EPA refrigeration test... don't do it.