Do you use the same amount of R-134A refrigerant as you would R-12 when charging a 1987 car's A/C?

Question

I have a 1987 Corvette that has had the new R-134A A/C fittings installed. The original sticker calls for 2.25 pounds of R-12 refrigerant (freon). I added the same amount of R-134A refrigerant but the system only blows "cool", certainly not cold. Should I add more R-134A? If I do, will I screw up the system? Also, bcause the low side fitting was too close to the evaporator housing, the guy could only vacuum & charge the system through the high side. We could find no leaks, BUT, the system blows cool but not cold even with high revs. Sometimes it blows cooler than other times which makes me think it doesn't have enough R134a in it. Any ideas? PLEASE RESPOND ASAP! Driving a Vette with only 'cool' A/C is no fun!

Answer 1

The unfortunate thing about R-134A is that it's not as cold as R-12. Second, you should never add more, by weight, than what the vehicle calls for. Also, I've never heard charging from the high side. You might not have enough freon where you actually need it. Maybe you should connect a gauge to the low side to find out if pressure wise, you have enough freon in the system.

Answer 2

you need a set of pressure gages for it when you do this ,you may have more freon than you have pressure,and that will cause an in-balance in the system,and not allow it to cool real good,that's why air conditioning work should be left people who do this all the time,it should hold about the same amount of freon ,but without the gage on it,you may not get it to cool right,there has to be so much pressure on the high side of it,and so much on the low side,if not it wont ever cool right,if you get too much in it,it could lock the compressor up on it also,good luck with it.

Answer 3

Yes you use the same amount "Capacity is Capacity" You will absolutely cause damage if you over charge a system. Blown seals on hoses will cost you hundreds to get replaced

Answer 4

charge up to 80-90% of original r12 amount and another thing i would take it back and make him hook it up to the low side are you kiding me thats what he said its too close to the evaporator housing?? who cares make it work there could be a pocket being trapped on the low side and thats whats messing up ur ac

Answer 5

I have never done this but my understanding is if you get any cooling at all with that conversion you're lucky. But this does not answer your question whether you have the right amount. Whoever is doing this for you ought to have answers.

Answer 6

You need to have the system retrofitted for R-134a.

Otherwise it will NEVER get cold.

Expect to pay $600 for parts and labor.

Or just enjoy the "cool".

Answer 7

if i remember correctly you use 80% the r12 weight. you would use about 1.7 lbs of 134a.never charge from the high side you will bend the valves in the air compressor

Answer 8

no the way to do it is watch the guade as u fill it.stay in safety zone,if higher it will break a line