Did I screw this up?

I found some r12 in my shed so I went and bought the little can piercer thing to put it in my '94 cherokee. I hooked it up to the low side, opened the little valve right by where the hose connects to on the back of the compressor, then turned the jeep on with the max a/c blowing. A/c got a little colder, took about half the can i'd say. I closed the valve, then removed the recharge hose and put the cap back on the fitting. I got into the vehicle to go autozone to take my retrofit kit back, and the compressor started making a whining sound on acceleration. Not a screech, just a whine. Should I pick up some oil and put it in the system too? Or did I overcharge it? Is it possible to overcharge it from a 12oz can? I opened the valve on the high pressure side and let some out (into a reclaiming can of course) and it still whines. Please help. Its 115 all weekend here in Phoenix!

A 94 takes R134a referigerant NOT R12 and the two are incompatible, you might have just toasted your compressor. You need to have someone evacuate the system and draw a vacumn for about 60 minutes to get all the old stuff out including the oil that was in that R12 can. Then Refill it with R134A and the correct amount of pag oil and cross your fingers.

R12 & R134a mix is hilghly acidic. Get that out of there ASAP. Remember just cause it's not pumping dosn't mean it isn't doing harm.

It has the threaded fittings and it says R12 on top of the compressor....is it possible that its r134a with R12 fittings?

whurston said:

It has the threaded fittings and it says R12 on top of the compressor....is it possible that its r134a with R12 fittings?

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No, R12 and 134A fittings are different. I don't know how likely it is that it really is an R12 system though.
Billy

I think it says on one of the little stickers that are under the hood.

Get your build date. R-134a was used beginning Jan. 1, 1994.
EDIT: Or just find the compressor model number. An R-12 compressor is a Sanden SD709 and the compressor for R-134a is a Sanden SD7H15.

Just checked, yep it's R12 for sure. So should I add some oil or release some pressure?

JeepFreak21 said:

No, R12 and 134A fittings are different. I don't know how likely it is that it really is an R12 system though.
Billy

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IT COULD BE. In 94 they came BOTH ways...

But the fittings thing....you should have not been able to mate them together.

whurston said:

Just checked, yep it's R12 for sure. So should I add some oil or release some pressure?

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You should CHECK the pressure. I'd probably still evac it and start fresh.

red91inWA said:

IT COULD BE. In 94 they came BOTH ways...

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Yes, but only those '94s actually built IN 1994 will have R-134a, hence my post about checking the build date (or the compressor model). Any '94 model built in 1993 will be R12.

Timber said:

Yes, but only those '94s actually built IN 1994 will have R-134a, hence my post about checking the build date (or the compressor model). Any '94 model built in 1993 will be R12.

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too bad they put the manufactures sticker face down on the compressor. But good point.