What to do with an 1991 Jamboree chasis AC with R12?

Most folks around here give me the deer in the headlight look when I recommend freeze 12. I recharge the neighbor's 4640 JD about once every two years. That thing will freeze you out on a hot day.

Most folks are just of a mind set that you gotta change to 134a.

freeze 12 gets as cold as R12 and is an 80/20 blend. No need to change oil. It's a direct replacement. It will serve you well. R12 is almost impossible to find and very expensive. NEVER use the R12 from Mexico. Some are blended with some dangerous chemicals.

I don't mean to hurt you guys feelings but all you have to do to convert is go to about any auto parts store and buy you a kit to go from R12 to 134,no flush no new dryer or none of that crap.The kit comes with hoses and all you need for about forty bucks but as stated you might have more problems than just a low charge

I had the system tested for leaks (none) and refilled with Freeze 12 for a $100. Works good for now.

Thanks for the replays.

Do the conversion so that it can be serviced anywhere.

+1 for replacing any marginal hoses or even the compressor at the same time.

Cry once and enjoy the cool air.

grodnay wrote:
Hi all!

Just bought this RV. The chasis AC does not cool. The compressor does not start. I can tell that this AC runs on R12 by the refill connection type. A workshop suggested a conversion to R134 for $550. They replace the also the dryer and accumulator.

What are my options?

Thanks,
-Guy

Have it converted over to 134A but make sure they fix any leaks that the system may have. If they have to replace any hoses make sure they use ones for 134A because 134A has a smaller molecule and tends to leak in places the R12 didn't.

Denny

R12 is so expensive now it's not worth putting it in. I've had two vehicles converted to R134 by just flushing, add oil, and new coolant. No work on the compressor at all and both work just fine and it's less expensive than putting in R12. I think for absolute maximum cooling you'd have to redo the compressor but this works fine for me. Get a price for each from your AC mechanic and compare.

As long as you can still get R12 I would use it. It's colder than the newer stuff and even the R134A is going to go away in the near future.

I have the same rig - same issue. On the few times I need AC in Oregon I crank up the generator and use the roof air. If cab air was a big deal I would likely buy original r-12 (still available) or try the Freeze 12 or other alternative before I converted the entire system - don't see much downside.

I would also suggesting changing to the replacement for R-12. Many times it is a blend of about 50% R-134a, and some other freons to allow the R-134a to work well with the older mineral oil in the older compressors.

The accumilator and freon dryer also have this old mineral oil in it, and if you decided to change to R-134a, you would need to replace them.

However if your system is leaking freon, it will do no good to install new freon on a leaking system, even the dryer will absorb moister after the freon leaks out, and will be no good after it has no freon pressure for about 2 months. So first thing they should do is install about 10 PSI of used freon, then about 80 PSI of nitrogen, and do a electronic leak check. If they find a leak, and can repair it, get a price first. Many times a hose or evaporator is about $75 - 200 for a hose, or $110 - 250 for a evaporator. Installation can be 1-2 shop hours, sometimes that is an additional $75 to $95 per hour. If no leaks are found at 80 PSI, they can increase the pressure safely to only about 175 PSI. There are parts not rated at 175 PSI inside the system, and it is best to not exceed that amount. Any good $250 electronic leak detector should find a leak at 150 PSI. If the system holds 150 PSI overnight, then it is leak free. Yes it might drop 3-5 PSI overnight just because the freon in the piping shrunk as it cooled off.

Good luck on the repairs!

Fred.