pishta

92 SC with 178,000 miles. I'm dying with no A/C in this car! Compressor spins, clutch seems to be engaging, no weird noises. I can put 50psi of R134 into this converted R12 system at a high idle and I get NO cooling on the inside vents. would anyone recommend more pressure/R134 into the system or should I start looking at a bad expansion valve or accumulator? These look to still use the older style capillary tube expansion valves. Accumulator is $24 and the expansion valve is about the same price. I just wanted to know if there was any obvious starting point. I do have A/C guages but am not sure what numbers Im looking for. Its about 80F here today. IT has not worked for years but its now getting some needed attention. I'm not equipped to put R12 back in as its >$30 a 30 year old can here and illegal to buy/sell/vent in any manner.

Klapped96

well long as we are on R134 I'd suggest charging it with some UV dye. after..iunno depending on how bad hours or a day or 2 of driving, check over condensor, lines, compressor. ect ect. I wouldnt go over charging this stuff but I'm no familiar with R12 conversions. sorry I can't be more help.

SC400slide

iTrader: (11)

I know this is more relevant to newer model vehicles, but still is applicable-you may have air pockets and need to vacuum out the entire system of all refrigerant then recharge. UV dye is also not a bad idea.

also, as a general guide, if the temperature outside is 80F, then low side should be roughly around 40-50 psi, and high side should read 175-210. Vacuuming the system out may be necessary.

Tallyhoe

Maybe check to see if previous owner didn't switch back the vacuum hoses on expansion valve? Leaving it in a winter setting?

RXRodger

iTrader: (2)

You have to start with gauges and the pressures they display. That will be the only relevant information. Give us the pressures you are seeing and we can help you. I have converted many many systems from R12 to R134 thru the years including my two street SC’s. There will be a minimal difference but still cools fine. Let us know what you find and we can go from there.

t2d2

iTrader: (8)

My first SC was sweltering, even with AC running. Turned out the heater control valve was no good, allowing hot coolant to circulate when it was supposed to be cooling. A visual check of its operation might be worthwhile.

Duck05

I battled several losses of refrigerant after the R12 to R134 conversion whereas after a full vacuum and refill the A/C cooled just fine during the summer. But, during the winter months with the A/C never used, when Spring rolled around the gas was gone. Finally replaced the condenser and with a new fill and the proactive UV oil it has been fine these past two years.

Reads like your system needs a complete overhaul including checking the O rings used during the conversion to R134. PITA for sure and the parts are pricey but should be fixed for good. It is after all a 30+ year old car….😎😏😎

pishta

Sounds promising. How many o ring locations are there and are they accessible? Ie, not behind the dash...that's not going to happen. Another related question: anyone ever run R-290 in an R-134 system? R-290 is A/C grade propane and is used frequently in refer units. R-134 gets expensive when you got a leak....

pishta

Well. Ill be damned. I put 50 psi of R22 in ( I found a 10 lb bottle in an abandoned building closet) and sure as ****, the thing is blowing cold air now! I believe my issue is a leaking valve on the compressor as when I pulled the manifold fitting off the compressor fitting and it was hissing, bad valve! It finally stopped after about 10 seconds (did it seat?) and I then put a valve cover on it I stole from my work truck. Well see if it works tomorrow but so far, I got cool air! First time in 3 years....