DIY R12 to R134a conversion

[Tuck]

I did this two weeks ago and so far, so good. I got a pressurizied can of flush, a filter/dryer, a blister pack of o-rings, two cans of R134a and a bottle of PAG oil to do the job from AutoZone. I already had a vacuum pump. I removed the compresser and drained the oil before replacing it with the PAG oil. Then I flushed the system, replaced the o-rings, and filter/dryer. Pulled a vacuum on the system and after seeing there were no big leaks, charged the system and was ready to go. BTW one of the cans of R134a had a leak stop in it and the other had a leak dection dye.

Why do I have a vacuum pump handy? I live in Florida and every time I took a car to get the A/C repaired it was $600. The pump was $400 @ Grainger.

Tuck

[SVX_MY_BABY]

Had mine converted in Dec 1999. Still cools great.

Replaced the dryer & o-ring. Only did the dryer because of the new refrigerant, nothing wrong with it.
Dryer No. 73031PA000, O-ring No. 73039AA060

Cost about 300.00 to diagnose loss of charge and do the conversion. If it's going to set you back 150.00 knowing you have a leak and there is a very good chance the Freon will leak again (which is environmentally bad) why bother? Just do the conversion.

[immortal_suby]

Did mine last summer with an advance auto retrofit kit - no o-rings changed or drier or anything other than the fitting which was included. Still on the original compressor at 239k. I just evacuated the system and dumped in the new stuff. Still cooling great so far this year and it is HOT down here!

[YourConfused]

I have no a/c and sighted my comp to condenser line due to the build up on it as the culprit. I am curious about how many people needed new compressors when the a/c went out. Over the last 10 yrs I hardly ever worked on a subaru, so I have no personal history with them like a honda, lexus, gm, or bmr. Looks like the system is super easy to work on so I am just wondering about common fail items so I can check their availability and prices. It's heating up in texas and it is time for the a/c to get a kickin.

[dcarrb]

Entering my fourth summer with the teal SVX running R134a; all I recall the mechanic replacing was the filter/dryer (aside from the condensor-to-compressor hose, which was weeping when I bought the car). The system cools just fine and has required no re-charge nor other attention.

dcb

[thumper_svx]

I almost hate to say it because then I KNOW I'll have problems, but with three SVX's, one Loyale and one Outback in the last 11 years, I've had exactly zero compressor failures. The Loyale was converted to R134 from R12 as well... and the Outback was R134 to begin with. Subaru compressors seem very well engineered and built (all of these 5 Subarus got over 150K except my current SVX which is at 137).

Now, that's not to say I haven't had problems with my other cars. I've replaced a compressor in a Chrysler Town & Country (twice) (122K when it was totaled), and a 96 Saab 900 Turbo (130K when sold, and the compressor was getting noisy again). Having said that, I had a Ford Escort I converted from R12 to R134 that was at 186K miles when I sold it and the AC still worked like a champ. Needed recharged about twice a year because the system wasn't very well sealed... but it worked well and never once did I have to replace the compressor.

Take from this what you will... just my observations BTW, when I replaced compressors they had completely seized in the Chrysler, and "burst" (Saab).

[davew833]

I used to drive mid-to-late '80s Hondas and I replaced a TON of compressors on those, mostly Nippondenso, some Hitachi. (Not sure who makes them for Subaru.) Seemed I could never keep a Honda system working! My advice on retrofits would be to avoid the so-called 'death kits' from AutoZone and Wal-Mart which promise conversion from R12 without doing anything but adding R-134a and oil. They WILL work for a while, but usually at the expense of killing your compressor. Also, most shops will not work on your A/C system if they know you've done a DIY conversion without purging and evacuating your system first. It's really important to get all of the old stuff before putting anything new in.

[Earthworm]

For those who don't already know there are about 13 o-rings in the entire A/C system. The most likely ones to fail are the ones on the top of the compresser.

Mine worked great ever since I converted to r134 by replacing all the o-rings, compresser oil and dryer unit.

Getting the system vacuumed is and the proper amount of r134 (professionally) installed is recommended.

[SSSVX]

Originally Posted by davew833

My advice on retrofits would be to avoid the so-called 'death kits' from AutoZone and Wal-Mart which promise conversion from R12 without doing anything but adding R-134a and oil. They WILL work for a while, but usually at the expense of killing your compressor.

Why would they kill your compressor? If you use the kit, but do it with the right way by vacuming out the old stuff and put in the oil and R134a in?

[SSSVX]

Glad to know most Subarus' compressors are reliable. But the one on my yellow one was out/seized at around 142K. But the one on my Teal one(still R12, low-low mileage) worked beautifully and never needs recharge yet for 6, 7 years.

Dave, do you think any difference for compressors compare as Group 1(92 and 93) and Group 2(94 to 97)? Just wonder do they change the compressor to work with R134a freon better after 94? Just thinking maybe the compressors on 92 and 93 work less efficiently after converted to R134a?

[immortal_suby]

update:
my AC blows so cold I have to turn the temp up to avoid freezing my hands. Drove to the beach this past weekend with the outside air temp gauge reading 100 and the AC was still super strong.

Still no problems with the DIY cheapo R12 to R134 conversion canister from advance auto and stock (240k miles) o rings.

[alia176]

So far, I've replaced the drier, all O rings, Evaporator (came with expansion valve), rebuilt compressor and I can't remember what else. I think I have a leak somewhere on the compressor somewhere. At least, that's what the A/C shop tells me anyway.

When I pull a vacuum in the system, will this really pull the oil out of the system as well? I thought this might only pull the old R12 and some oil. Technically, I should remove the comp and drain the oil the old fashion way. Let me know if this sounds right. I'll be using a Robinaire vacuum pump for creating vacuum.

As far determining how many cans of R134 to dump into the system, I'm guessing that I should have the hi/low press gauge set to tell me. However, since I'm suppose to dump in more R134 than R12, due to lower BTU, I'm trying to figure out what psi should I aim for on the hi/low press gauges.

Thanks.

[immortal_suby]

Well, I guess 4 years ain't too bad. Leaking AC system now from the connection on top of the compressor.

I hope my universal O-ring kit is made of the one of the accepted materials, or it's time to order new rings.

[torxxx]

I've had mine self converted for almost a year now and it still works fine. all I did was purge the system, put a vacumn on it for 20 minutes to get all the oil out of the system and then injected new 134a oil and was good to go. finding fittings was the hardest part for me. the retrofit kit didnt have the right fittings

[92 SVX]

I was told that draining all the R-12 oil would be counter productive, sure some will come out when you vac the system but its helpful to have some in the system it will coat the o-rings and keep the R-134 from eating them.
You just need to vac the system and add the PAG oil then the R-134.

My system was converted some point before I bought the car, they have a sticker on the rad support, I assume it was leaking as they indicated they put dye in the system
It has never worked that well I have had several problems with it I dont think they replaced any parts they just put the screw on adapters for fitings. Found that my low side port fitting was leaking so after recharging I took that fitting off appears to have held for 6 months now.