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740 Service R12 or convert to R134-a

iHateVolvoPeople

Active member
Joined
Feb 1, 2014
Location
Midwest
Just as a conclusive post so you don't have to go reading
We decided to simply replace the R/D (cheap insurance), vacuum the system to remove moisture, BUT then we depressed the schrader valve to get pressures back to 0 (do not charge a vehicle with ES12A while under a vacuum. Do it at 0inHg). Then we charged with the correct amount of ES12A and the ac blows about 40F no matter how hot.

>>>>>>>>>>>>>>Original Post Below>>>>>>>>>>>>>>>>>

1990 740 LH2.4

AC doesn’t work. Jumped the compressor with 12v and it engages like it should. Car sat for a couple years so I’m thinking it all leaked out, there was green sludge on the bottom of the compressor when I looked underneath the car. I have service records for a $2.5k dollar Volvo dealer visit from 10+ years ago. PO had a new compressor and a buuuunch if other AC work and other stuff done.

I will likely pay a 'professional' to do the work so I don’t blow myself up. I’ve recharged the r134 systems on the 93 cars but this is different.

Do I have them pull a vacuum, then recharge with r12 (or r12 equivalent) + Volvo lube? Or do I do the same but just throw r134 fittings on and fill with r134 + volvo lube? I’ve read something about r134 leaking out of r12 systems due to molecule size. I’m not wanting to pay $300+ to tear the system apart and replace it with r134 components. Also wondering if there’s a substitute lube I can use where I don’t have to drive to the dealer.


I’m all about quick and dirty jobs but this is for my SO’s car so I want it to be reliable and cold for her.
 
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I say replace the drier at a minimum, and maybe look into a substitute like Duracool. If you use R134 use ester oil.
 
Add to much oil and performance can suffer. Too little in there and the compressor dies.

There isn't really a way to tell how much is left in the system. So I just add an ounce sometimes for good measure. Or sometimes, add nothing.

Ester oil seems like the way to go. So yes, recover, vac down, add correct amount of refrigerant and maybe some oil. Or not.
 
Add to much oil and performance can suffer. Too little in there and the compressor dies.

There isn't really a way to tell how much is left in the system. So I just add an ounce sometimes for good measure. Or sometimes, add nothing.

Ester oil seems like the way to go. So yes, recover, vac down, add correct amount of refrigerant and maybe some oil. Or not.

:uh: lol I?d rather performance suffer a bit than to launch a compressor:lol:

New receiver driver>pull a vacuum>throw 1oz of ester oil in>install r134 adapters and fill with r134.

But pay a professional to do all this.
 
You need to find out why it failed. It prob leaked out.

1 oz oil for good measure should be fine.
 
Isn?t it somewhat normal to leak out over time? If the leak is slow enough to last 2-3 seasons then I don?t care.

Yes. All automobile AC systems leak over time. Don't bother with R-134A. Just put Enviro-Safe ES12A in it and be done. You don't have to change anything. It outperforms R-134A and is half the cost.
 
Yes. All automobile AC systems leak over time. Don't bother with R-134A. Just put Enviro-Safe ES12A in it and be done. You don't have to change anything. It outperforms R-134A and is half the cost.

Is that filled using the stock r12 fittings? I was just informed of a local Volvo shop near me who can possibly charge and lube the system for me.
 
duracool. I did the 134a with new drier and new orings. Never cooled well so I had the 134a takin out and pumped it down then added duracool. Its cold as ice in 100 degree temps. 134a does work but the system has to be setup for it. Bigger condenser different valve etc.
 
Yes. All automobile AC systems leak over time. Don't bother with R-134A. Just put Enviro-Safe ES12A in it and be done. You don't have to change anything. It outperforms R-134A and is half the cost.

Alright getting some mixed responses from you folks so I will do some research. I was never actually thaaat impressed with r134 in older cars (though my 240s are exceptionally cold after about 10 damn minutes).

Question now seems to be duracool or the Enviro-Safe ES12A. Benefits/downsides to each? Can I use stock r12 fittings for each?

If I can have him fully evacuate the system I?ll just pick up some ester oil and have the ac guy put in the proper amount of that and proper amount of refrigerant.
 
There have been some positive results using propane. It's common in other countries, and is basically what Freeze12 is. You'll need to come up with some fittings to get it in there though.
 
I get 40* at the vents with an aftermarket parallel flow condensor and DustOff Keyboard duster as a R12 replacement. 12 bucks for a 4 pack at walmart, I charge roughly 28 oz into it and call it a day. Lasted a year before it leaked out, another 12 bucks and its blowing freezing again.
 
Find the source of the leak with a UV light, replace the part that is the source of the leak, replaced the receiver/drier add two ounces of POE(ester oil), vac the system down for a good half hour to hour. Then add 2 and half cans of Duracool and call it a day. Did that to my Wife's 244(which has about the same size system) and it runs cold as ice.
 
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