The Air Conditioning in my 89 Jeep Cherokee stopped working at least 15 years ago. At the time, I took it to a AC specialist who pumped it up with nitrogen, I drove it for a few days then brought it back where he confirmed that I had a leak which he said was related to seals. Anyway, he didn't seem to think that it was fixable or maybe it was just too expensive (I always thought it was odd that he didn't try to hard sell me on some expensive rebuild). I didn't really pursue it after that because here in Vancouver, there are typically only a few days a year when AC is needed. At least that's how it used to be. Seems to be more hot days than there used to be, especially on my annual August camping trips to the interior.

In any case, I thought I might try to get the AC working again. The original system is R12 so I need to use some other refrigerant. 134 is an option but upgrading to that from an R12 system seems to have a bunch of issues. Several buddies have successfully used something called 12A (I think) sold under various brand names which is supposed to be 100% compatible with R12 systems. So, I've got a couple of questions:

• Since my compressor hasn't run in more than a decade, how likely is it to be seized?
• Even if the compressor isn't seized, how likely are the rotary seals (if that's a thing) liable to survive a re-start?
• Is there something I can do ahead of time to better condition the compressor in preparation for a re-start?
• If the compressor is NFG, what other compressor options should I consider: junkyard replacement, new or rebuilt R12 compressor, replacement R134 compressor, other?

To complicate the plans, my old jeep doesn't have a lot of life left in it due to rust (otherwise in very good shape and relatively low mileage) so I'm limiting the funds available for the rebuild.



Thanks for any advice.

 

I've converted many a car over to 134a. It's cheaper than any other option and is readily available. You will need a new receiver drier and you will of course need to repair whatever the original leak was.you can remove the drive belt and rotate the compressor clutch by hand (center portion not the grooved portion) to get it moving and tell if it's siezed. Usually when I check for a leak I recharge the system properly not with nitrogen(which is a viable option). And a good number of customers don't mind having to do that once a summer instead of a more costly repair.

 

Thanks for your note Red.

I thought there are compatibility issues with residual R12 mineral oil already in the system when converting to R134. Also read that new hoses are required as the old R12 spec hoses may be permeable to R134. Does that make sense?

 

Bucko,

I literally just finished redoing the AC in my 87 Waggie. Firstly, I'd suggest replacing the compressor for a couple reasons; A) if it starts up again and starts to fail in short order, you'll have wasted money on the refurb/recharge, and B) if it fails you could spread metal bits throughout the system. Plus they aren't all that expensive anyway for the peace of mind.

As mentioned above you'll also need a new receiver/drier and expansion valve. These parts aren't all that expensive.

You'll also want to ensure your condenser and evaporator are in good condition. Depending upon where the leak was before you may need to replace one or both of these. Condensers can be had for about $60 on rockauto. If you can use your old one though, do. But you'll prob need to get it flushed/tested bc many years of sitting like that probably has led to crud build up/solidification.

You'll need the evaporator in the dash at least flushed and prob vacuum tested.

Lastly, and this is the big deal, you should get all your hoses replaced/re-made. I had a local auto A/C shop here in Dallas make me some fresh ones. These things get old and dry rot. I'm pretty sure I saw the spot where mine leaked and ultimately caused my system to fail. All the new hoses came with new seals.

I saved myself a lot of money by installing it all myself. It is incredibly easy. You almost can't mess it up. Do remember to drain the "shipping" oil out of compressor and into a solo cup before you install it. Manufacturers vary the amount of oil they put in there and you need to have a specific amount for the system to work optimally. Just tell the shop that you have no oil in your fresh system and they'll know how much to put in it for certain when they charge it for you. After I had it all buttoned up I took it back over to the A/C shop, had them vacuum test it and give it a charge. She runs nice and cold now and I'm a much happier camper.

Good luck!

-Matt

 

I've converted a dozen or so old volvos, an old mercedes, a 65 lincoln continental. Kept original hoses. Yes they may leak due to age but, meh. If you can get the ac to last each summer you can recharge it for 4 or 5 summers before it stops making economical sense.

 

Another possibility is something like EnviroSafe or DuraCool hydrocarbon refrigerants. They work very well with the old mineral oil and are actually more efficient than R12. The main issue with these is that they are flammable. The safety record world-wide is very good, and "tests" that purport to show them to be dangerous that I've seen are either rigged or someone did something really stupid like smoking when working with them.

However you'd need to check the laws in your jurisdiction as to legality. As far as the feds are concerned unless things have changed the last few years these refrigerants are legal to use, or at least not regulated, when introduced into an R134a system. This includes an R12 system that has previously been converted. (So if ever questioned about it stick to your story that you converted to R134a first. )

The other issue of course is that no shop will want to touch an AC system if it uses an alternative refrigerant, you would be committing to doing your own AC work and anyone you sold the vehicle to should be informed.

https://www.es-refrigerants.com/

http://www.duracool.com/

 

I'm running EnviroSafe and I've been satisfied with it. Just my $.02