• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Diesel 240 AC

Cwazywazy

Cwazywazy

Single jingle
Joined
Aug 20, 2016
Location
Granby CT
This isn't my first rodeo with 30+ year old AC, but this car is different because it still has about 15PSI of what I assume is the original R12 in it. No stickers or adapters and the drier looks original. Jumped the pressure switch and the compressor kicks on fine.

I originally assumed it would be completely empty like my other cars and I've already ordered a new drier and envirosafe. So the way I see it is I have a couple options. A, replace drier and fill with envirosafe like I originally planned, or B, find some R12 and dump it in there as-is. Opinions?
 
R12 leaks out slower, but being early, it probably has shrunken o-rings and a marginal expansion valve.

Evacuate and sell R12? 15psi might just be a tiny bit of residual whatever on a warm day.
 
Kjets On a Plane said:
R12 leaks out slower, but being early, it probably has shrunken o-rings and a marginal expansion valve.

Evacuate and sell R12? 15psi might just be a tiny bit of residual whatever on a warm day.
Click to expand...

Oh yeah, it is warm today. 15psi is almost nothing but it does tell me that there's no major leaks or anything.
 
There's no liquid R12 in there at all, it's just a tiny bit of residual gas at only 15 psi. I'd have it evacuated and fill it with hydrocarbon substitute, either that or go through the whole system and set it up for whatever you want. Given the remaining pressure there's a reasonable chance it's not leaking much at all.
 
TestPoint said:
No major leaks at 15 psi.

Your expansion valve is almost certainly useless after the 30 years.
Click to expand...

Is that something I should replace? Or is there a decent chance it'll work? I hate dealing with that butyl crap they used to insulate that stuff.
 
:lol:
15psi remaining on a warm day and "no leaks" are probably mutually exclusive.

Diagnose the leaks/good luck?

Usually on the POS Volvo system the compressor has more or less worn out and ground itself up on a low/marginal charge and taken the expansion valve with it. Have fun.
 
The expansion valve I pulled out of my '82 Diesel with 180k miles was so packed with hard brown junk that it would have never allowed gas to expand.

Any system this old needs to be flushed out and the dryer and expansion valve replaced. I would add the compressor also. It may work for now but for how long. Maybe, just maybe recharge with R12 substitute to match the mineral oil in the compressor and hope.

I ended up with a new compressor, new expansion valve, new dryer and flushed the rest with brake cleaner and compressed air. New PAG oil and R134 and I can get to 52 degrees vent temp. Volvo spec is 48 to 54.
 
TestPoint said:
The expansion valve I pulled out of my '82 Diesel with 180k miles was so packed with hard brown junk that it would have never allowed gas to expand.

Any system this old needs to be flushed out and the dryer and expansion valve replaced. I would add the compressor also. It may work for now but for how long. Maybe, just maybe recharge with R12 substitute to match the mineral oil in the compressor and hope.

I ended up with a new compressor, new expansion valve, new dryer and flushed the rest with brake cleaner and compressed air. New PAG oil and R134 and I can get to 52 degrees vent temp. Volvo spec is 48 to 54.
Click to expand...

Yeah, envirosafe is the best refrigerant I've used in my cars. I've done two 30+ year old AC systems already and neither required much. I didn't even replace the drier on one and it worked fine for a year before I parted it out. When I jumped the pressure switch the compressor didn't make any noise. At least not anything that I could hear over the engine.

I'll suck the system down and see if it holds vacuum for a good while before doing anything to it.
 
I have yet to replace a compressor in a Volvo. I converted the AC in my '87 to R134a with the original Diesel Kiki compressor back around 2002 and used it for 15 years. One recharge was required about 5 years ago.
 
Okay, maaaybe you guys were right on the expansion valve. I replaced the drier and it held vacuum so I put in most of a can of envirosafe. Pressure only drops to about 20psi on the low side vs ~50-60 with the AC off. On my turbo at around this level of charge I saw vacuum on the low side.
 
Replaced expansion valve with a new one at 4 turns out. Pulled vacuum and dropped in some envirosafe. Exactly the same. Takes forever for low side pressure to go down and to suck in refrigerant. There's maybe half a can in it, tops. I remember with my other cars low side pressure would drop instantly if I revved it while charging. High side hoses don't feel warm at all and vent temps are maybe 1 degree lower than ambient. Obviously there isn't enough refrigerant in it but I don't really wanna waste it if there's something wrong with the system.

Looked in the old expansion valve and there was a tiny bit of gunk in the screen. Not enough to impact performance, I think.
 
compressor is most likely failing if it cant draw the suction side down. they do wear out.

if you want to test the performance of your ac without wasting all that envirosafe (which i use and love but my 940 is converted R134A and blows like the artic)

grab a cheap propane torch and a R134A charging hose and cut the end off with enough hose to slide on the end of the torch (torch tip removed) and use that for a "test" refrigerant. I was using R134A to test my system since i have the ability to recover and recycle but im so happy with the 134a performance i left it.
 
I kinda feel like it's a blockage and not the compressor, but what could it be? I've already replaced the drier and expansion valve. Didn't see any gunk in the lines or anything.
 
itsacrazyasian said:
if it was a blockage, your low side would have gone into suction and your high side would have increased.
Click to expand...

Oh yeah, that makes sense. I wasn't really thinking about it.

So uh, guess that means my compressor is trash. I have the one from my parts car which is good, but I think it might be different and I already told someone they could have it.
 
This is with something like a 1/3 charge of envirosafe:

vgsWwtZh.jpg

QmreKSoh.jpg
 
Sooo last year I swapped over the compressor from my old wagon and the AC worked great. Then sometime a month or two later I left it idling with the AC on for a couple minutes and when I came back all the refrigerant was spraying out the front. Since it was getting cooler I just ignored it until now. I can't find the leak. I've been trying with soapy water and compressed air, just can't find it. Replaced both condenser o rings and that made no difference. I can hear a small hiss around the passenger side of the condenser. I'm thinking of just replacing the condenser.
 
Bought a junkyard condenser and of course the top line has a pinhole. With the old one out I finally found where it blew, little hole hiding behind the bracket.

Already have ES12a and a new drier, just need a non-holey condenser. Last year the AC worked nicely with ES and I think I'll open up the valve a little bit when I get a new condenser.

I wish it was as easy as my first wagon, all I really did was put in some oil and R134. Worked pretty damn well until I parted it out. (Its condenser is in my other car now.)
 
You must log in or register to reply here.
Back
Top