AC resurrection R134. Super Coupe is fighting me

figulaz

SCCoA Member
I need help with the AC. I rinsed condenser changed hi pressure hose with filter and receiver dryer rinsed compressor and added oil. Vaccum pumped to 35 hg and held for 30 mins. I went to charge and it seemed to go high like 55 per the gauge on the can right away I’d bleed out some pressure for the high side but it was warm to ambient temp. Same deal on low side and neither the line and can ever got cold. At one point compressor would cycle on and off but at pretty high pressure. Adjusting screw at the receiver pressure switch didn’t seem to help. Switched out another used switch. No help. Jumped switch with wire and got Compressor to cycle. Now show 45 hrs but air off the valve is warm. ???? What am I missing. Something blocked? New receiver pressure switch??
 
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When you say "rinsed compressor", how did you rinse it?

That's one of the items you can't use A/C flush on; the flush will destroy the seals inside.

Second, it sounds like you have one of those "can topper" gauges; toss that piece of crap, and get a REAL manifold gauge set so you can monitor low AND high sides both.

Third, about how much R134a by weight have you put in? The R134a load will be about 70% to 80% of the R12 load by weight, so if it says 40oz of R12 under the hood, you'll expect about 28 to 32 oz of R134a.

RwP
 
The compressor was from an old engine pull and looked dusty and open to the environment so I poured ac flush in and cycled it through on the bench with a clutch wrench tool. New seals on top. I didn’t think it would harm the inside and it cycles on and off but maybe it’s ruined. The manifold gauges I have are old school and I used it for pulling vacuum.i used a 22 oz can and r 134 adapter to try and fill plus a few ounces of oil. As I try and fill it would go into the red pretty quick on the cheap can gauge and I’d purge through the hi side to relieve pressure and it would come out about ambient temp. That has me confused too. How can refrigerant pressurize a system that had vacuum on it and ambient air come out
 
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Keeping adding R134a until the compressor stops cycling....once the compressor is on 100% of the time, add until you get to the recommended pressure range or the refrigerant capacity.

The high pressures will scare you when you first start with a top-off can, but don't worry about them until the compressor clutch stay engaged.

Two of the small cans should get you where you need to be, but the max capacity is about 2.5 cans. It won't really cool any better that I have noticed beyond the two cans.
 
The high pressures will scare you when you first start with a top-off can, but don't worry about them until the compressor clutch stay engaged.
Yeah. >250 psi is pretty standard for r134 on a hot day. Important that the fan is running all the time.
Two of the small cans should get you where you need to be, but the max capacity is about 2.5 cans. It won't really cool any better that I have noticed beyond the two cans.
Right. You'll struggle to get it to take much more than that, and it may not cool any better. The important part is to get it to slowly and evenly draw down to a low side pressure of about 21 psi and then it should cycle.
 
Thanks guys. Turned out to be a bad pressure switch and not enough refrigerant. Plenty cold now. 1st SC with working AC. Wooohhoooo!
 
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