Propane for A/C

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,867
Points
48
Make
Saturn
Model
SL2
Year
1995
Miles
250K
Engine
1.9L DOHC
I hope to get some useful discussion, but expect to get some blasts, too. I will try to keep "thick skinned"!

I have read hints that R-290 (propane) can work well in place of R-134a; but is illegal here in USA due to fire danger. Being a curious soul, I wanted to try anyway...

It is a '95 SL2 and the A/C has not worked for many years. No known damage, but just stopped cooling and it isn't my primary SL2 so I figured to never bother fixing the A/C. Nothing to lose, right?

I connected the gauges, no pressure in system, so I pulled a vacuum and it held fairly well. So, I charged it with barbeque propane; left the PAG oil in there.

Cooling does definitely seem good. I can get 20-30F at the dash outlets. The low-side line into the compressor has frost on it, even with hot air from the radiator blowing on one side of that line and the exhaust manifold about 6" away on the other side. Pressures are different, of course. I settled on 300-350 psi high with the low staying fairly constant at 20 psi. I tried varying the charge a lot, going up high enough that the compressor was cycling on/off from the high switch (about 400-450 psi); that 300-350 seems to be best so far. With propane, I had no qualms about adding/bleeding to try a lot of different pressures.

So, I'm trying to decide now if I should go ahead and flush all the PAG and replace with something that is compatible with propane and R-134a (POE?) and recharge with real R-290. I don't really need working A/C in this car, but would sure like to prove out a replacement for R-134a; especially since it seem to cool so much better!

PS: I figure the charge I have in there is about equivalent to 1 qt of gasoline, and would have to get "trapped" just right, if released, to keep in the 2-10% flammabilty range to burn at all. I'm not too concerned about the fire dange
 

JackC

wrench
Joined
Nov 14, 2006
Messages
1,691
Points
38
Location
Nothern California
Bill: Interesting. I have 4 oz of new PAG 46 you can have if you need that type. It came with the new compressor I installed but I used Ester 100 Vis 150 oil instead.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,867
Points
48
I have PAG oil, I think it would needs to be removed to continue using the propane. My immediate wonderment is whether I should take out the low-grade barbeque propane and back-fill with a bit of R-134a, to preserve the system until I decide if I am going to do the propane conversion properly.
 

JackC

wrench
Joined
Nov 14, 2006
Messages
1,691
Points
38
Location
Nothern California
You said "I pulled a vacuum and it held fairly well ", So there is a leak? Why not leave the propane in to see how fast it leaks down before you invest an any more labor or R-134a. On the other hand I think you still have R-134a in that large tank. Just a thought.
 

NickD

wrench
Joined
Aug 28, 2007
Messages
5,127
Points
48
Your 1995 Saturn should be R-134a, EPA pushing this stuff like crazy back then condemning R-12, just got one Gore lover stating R-12 was diluting the Antarctic ozone layer. It was being diluted all right, but not by CFC refrigerants, but by lack of sunlight about six months out of the year.

A guy by the name of Oz was pushing Propane, but mixing it with Butane that was very close to R-12, but was condemned by the EPA as a fire hazard, but this never was there concern, but these same hypocrites are now condemning R-134a claiming it causing global warming. So now pushing

R1234yf is a hydrofluoroolefin (HFO) refrigerant. HFO refrigerants are composed of hydrogen, fluorine and carbon atoms that is indubitably a fire hazard. Not exactly cheap, runs around 60 bucks a pound. Fortunately I have some R-12 left for my 88 Supra, but in the last 32 years, I only lost 3.3 ounces. No way can this car be converted to R-134a. R410A ain't exactly cheap either and doubling the pressure of R22.

R-134a has been nothing but problems with those stupid quick coupler ports that leak like crazy, tube and fin condensers were next to bullet proof as oppose to these aluminum foil condensers, one little stone can wreck these.
Land of the free is becoming BS, first was the IRS that is just as bad as the German Gestapo, then joined by the EPA. Had these guys on my back for years, but none of them don't even know what Sodium chloride is. Just a bunch of egotistical idiots and most wouldn't last five minutes in private industry.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,867
Points
48
Jack. your reply got lost because it came in just before some drivel. By "fairly well", I mean it dropped from 29" to 27.5" in 14 hrs. That is not as good as I would like, but far better than most shops will do. Remember, this vacuum testing has all the hoses, gauges, valves, and quick-connects attached, I'm testing those connections as well as the car A/C plumbing.

I didn't want to leave the propane in because it was BBQ propane, not purified "R-290", and because I don't know if it and the PAG are compatible. I took out the propane and back-filled with a bit of R134a, just to keep atmosphere out. Before I removed the propane I ran the A/C again, got 17F at the dash; but that was with condenser and under-hood plumbing still pretty cool. I expect the dash temp would have crept clear up to the mid-20F range again once everything came up to normal temp. Still, I feel pretty certain propane can cool, and cool better than R134a. If I can settle on how to flush the PAG (if necessary) and what to replace it with, I will probably go back with some more BBQ propane and run it for a while. Unfortunately, compressor manufacturers seem to insist on just an exact type/weight oil (PAG 100 in this case), there is much FUD out there about what will happen if I vary the oil type. I'm on my own with this...

PS: I measured the propane I took out, it was about .657 lb (5.8 cubic feet)
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,867
Points
48
I have settled on putting MO (mineral oil) back in, but any suggestions for getting the PAG out? I think isopropyl alcohol flushes the PAG, but how to circulate it effectively? My only idea is to remove the low (suction) line from the compressor and feed isoP into the compressor low port while slowly rotating the compressor by hand and catching flow out of that disconnected low line. The compressor should pump the isoP through the whole system.
 

NickD

wrench
Joined
Aug 28, 2007
Messages
5,127
Points
48

Recommended auto AC flush, enjoyed using R-12 for around 34 years, used NAPA lacquer, they stuff they sell at hardware stores called lacquer thinner is anything but lacquer. Only had four R-134a cars since 1994, never removed the service caps, and lucky, never got a stone chip on those aluminum foil condensers. So never had to do any R-134a servicing, around here, only about two months out of the year, but the bodies are rusted out before the AC crapped out.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,867
Points
48
Wow, that is the first info I have seen that indicates the PAG can stay in there when going to propane (R-290)! Before, I was only seeing MO, AB, and sometimes POE. I'll have to research some more, This would be real easy if the PAG can stay...

Others note: I am not asking what to flush with, but how to mechanically do it without taking everything apart for a gravity-drain.
 

NickD

wrench
Joined
Aug 28, 2007
Messages
5,127
Points
48
Need a charging station for that, flush, vacuum, and charge. Read that dangerous with propane, witnessed a thousand gallon tank of propane on fire, the flame shot straight up. And propane doesn't burn unless you have oxygen and ignition.

Was a program on shooting down vehicles using hydrogen as to how its not dangerous, least not compared to gasoline, also burns straight up where gasoline spills all over the place. Sister-in-law was in a GM pickup when they installed the gas tank under the seat. That was stupid, burn to death when she was alive. And that gasoline spread all over the road.

Not sure why you are fooling around with propane anyway, insurance regulations, 12 ounce can is only four bucks. I purchased a 30 pound can of Dupont Suva, still sealed. Always struck with DuPont, they called R-12 Freon, but most people call any refrigerant Freon. Before R-134a, a 30 pound bottle of "Freon" was only 25 bucks. Major cost was the container. Some guys modified these tanks for recovery, but intended to be throwaway.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
11,187
Points
63
Location
St-Hyacinthe, Quebec, Canada
@newbie jim, that is exactly what I use. But mine is otc brand, but in essence exact same.

But I have a question, mostly on my bosses parts, do we NEED another flush unit slash kit for the r1324y?

BTW, thx for your contribution Jim M. It was a very nice link. Probably I just answered my own question for the boss. Will make, yes, make a kit for the new stuff. I was dwindleing in my mind to convert this old r134 flush kit but the price of doing so is cost prohibitive, probably just buy a unit that is plug and play out of the box.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
11,187
Points
63
Location
St-Hyacinthe, Quebec, Canada
@Bill, my idea is just use what is in it. It IS compatible.

And as for disclaimers, yeah a pound of propane is flammable. A 40 pound tank times 2 on a RV sure is a fire ball in a gotcha moment, but I dont see mass killings from a condensor blowing apart and killing a whole city from a 1.45lb charge.;):eek:$.02

Ok, I am off on a tangent, just had a real good talk with my son, his first break up with his GF. Oh joy, the life of a father. I told him that the mother of women aint dead yet. That went 30 k feet over his head. Kids 17. He also wants my old echo. I said, be sure to pass the auto class, then we will get serious.
 
Top