Quick and dirty fix for R12 a/c system?

the A/C in my Miata died a slow, lingering death, which leads me to believe I have a very slow leak... somewhere. A/C systems are second only to automatic transmissions in the "I've taken the online courses, but as far as I'm concerned they work by dark magic" category. In 2 weeks I'm taking a road trip to Texas for MiataWorld II, and I'd love a quick and dirty fix so my A/C lasts at least through the long weekend. Of course my car is an R12 system. Are any of the store-brand conversion/refill kits of any value? Is there any chance I could find a leak on my own without diagnostic equipment?

Refill with R12 and get a good belt. A few years ago the AC quit working on our Miata and I was ready to just live without. After reading numerous threads on the .net about how a new belt and a charge saved almost every Miata AC I gave it a shot. It has performed flawlessly ever since.

Last I checked R12 is hard to come by?

yes r12 is hard to come by. you can convert it pretty easy though u just need to evacuate whats inside and change the fittings to r134 fittings and fill iwth r134 and some dye. It will work good and the dye will help you spot the leaky part if it is leaky. Or find someone with r12, an r12 only machine and put dye in with that also.

I don't think I have to worry much about evacuation, I believe its all gone.

alrite then blow out a the lines gently with some compressed air and change your fittings, some of those retro fittings thread right on to the old r12 ones and then take it some where to get it vacuumed, charged and dye injected.

if it is all gone i dont think your compressor will even cycle on so check it out.

For cheap fix, just buy the R134 kit that comes with the fittings, a can of R134 and a gauge built into the hose ($30 or so I believe). Since it's already evacuated, put on new fittings and add R134. I've done this with my 93 and it works great. It would probably work better if I pulled a vacuum on it and then put in R134. I planned on buying a vacuum pump from HF for that reason, but decided to try this first and this works so well, I've never bothered. I redo it about every 8-10 months or just before the summer hits. At a cost of about $6 per can (I can usually only get 1.5 in), that's about $12/year.

I have some (3 or so) cans of R12 sitting around.

If your R12 leaked out, you now have air (and moisture) in the system. A vacuum -needs- to be pulled on the system before recharging. Moisture will kill the compressor in short order.

Bumboclot wrote: If your R12 leaked out, you now have air (and moisture) in the system. A vacuum -needs- to be pulled on the system before recharging. Moisture will kill the compressor in short order.

Werd. Not only that it will kick out on high pressure constantly.

I've seen some people just top up thier r-12 systems with 134a. Its not supposed to work, but it does. I knew one miata that ran it all summer (in hot / humid detroit no less).

Kendall

You can do a quick check by pushing in on of the AC fitting and see if there is any pressure (only do this while the car is not running and hasn't run for a few minutes). BTW this is technically an EPA violation. If there is pressure, you cheapest fix is to refill it with one of the many blends that are offered (envirosafe, freeze-12 etc.) and make sure that at least one can has some sort of leak stop in it. The blends are generally safe for r-12 and r-134 systems. I am not sure if a shop can or will recover a blend, so you will definitely want to tell anyone that works on the car that it has a blend in it.

Yes, 134 is supposed to leak out of R-12 systems (smaller molecule), but there have been many case where this did not happen (they suspect the oil that has been in the system all those years has effectively created barrier hoses)

Be aware: California is about to stop selling small refill cans over the counter, not sure about other states. I am sure you will still be able to mail order though.

R12 is easy to come by, at least down here in San Antonio.

Spend $25 and get your EPA cert.

O'Rielly's sells it for $38 a can, but I've had good luck posting a wanted ad on Craigslist and scoring for about $20 a can when I need some.

I have a few cans of R12 lying around, too. I should sell them, like I sold my 400 SBC. Who uses SBC's anymore, when LSx's are much better?

Most parts stores have inexpensive R134 conversion kits. Cheaper than R12, especially when it needs refilling.

m4ff3w wrote: R12 is easy to come by, at least down here in San Antonio. Spend $25 and get your EPA cert. O'Rielly's sells it for $38 a can, but I've had good luck posting a wanted ad on Craigslist and scoring for about $20 a can when I need some.

Is that R-12 coming in from south of the border?

curtis wrote: then take it some where to get it vacuumed, charged and dye injected.

I didn't come to the GRM boards looking for the advice "pay someone to do it the right way!" Perhaps I should have included "cheap" with "quick and dirty."

FWIW R12 is pretty environmentally unfriendly. I can't speak for car mechanics, but in the HVAC biz, if the leak requires frequent topping off, you are required by law to fix it.

alrite quick and dirty you want? go get a can from one of these dudes or find one and just get one of those crappy filler hose and gauge from discount auto or find someone with one and put it in and see what happens.

or you can do it the right way. whatever.

spitfirebill wrote:

m4ff3w wrote: R12 is easy to come by, at least down here in San Antonio. Spend $25 and get your EPA cert. O'Rielly's sells it for $38 a can, but I've had good luck posting a wanted ad on Craigslist and scoring for about $20 a can when I need some.

Is that R-12 coming in from south of the border?

IIRC, the penalty for bringing a pound of R-12 across the border is higher than the penalty for a pound of marijuana.

spitfirebill wrote:

m4ff3w wrote: R12 is easy to come by, at least down here in San Antonio. Spend $25 and get your EPA cert. O'Rielly's sells it for $38 a can, but I've had good luck posting a wanted ad on Craigslist and scoring for about $20 a can when I need some.

Is that R-12 coming in from south of the border?

Which? The stuff from O'Rielly's or the stuff I get for $20?

The stuff I get for $20 is usually cans people have had for years or oversupply from a shop.

I don't know where the stuff from O'Riellys comes from. I never think to look at the labels.

The cheap fix...Buy a 134 conversion kit. Stop by the hardware store and get a t fitting and a small valve. Cut the fill hose and install t fitting and valve to attach vacuum pump. Install the conversion fittings. Borrow or rent a vacuum pump. Hook up and run for 30 minutes. Close valve and fill with 134. I use a medical vacuum pump I bought at a yard sale for $10.00. It only pulls about 19" of vacuum, but it does the job. I have converted several cars this way with no problems.

I came to the conclusion for my car it isn't worth trying to refill the system with r12 because the original AC(after federalization when they got rid of the behr AC and put the POS york compressor) is a pig. I'm going to save my money and get a sanden that uses 134A. Around here the R12 sells for 35$ a can(I think 12oz) on CL, I need about 40oz of r12 so I'm talking around 100$ in refrigerent vs. 20$ for the 134A.

I guess they make r12 substitutes also which are a mix of volatile gasses, but should work. Good luck!

I recently put Freeze 12 , which is 80% r134a and some other mixtures, in my 93 G20. No, you can't use it to top off R12. Since it was already empty, I just pulled vacuum, installed adapter fittings, and charged it up. No need to flush, change the seals, or put a different oil in order for a r134a work right. On my BMW, since it needed a new compressor and hoses, I converted to r134a.

anyone ever converted to propane? I'm told it works just as well as R-134... a guy I knew in houston swore by it!

I believe propane works fine and it may be a component in some of the blends. The real issue is of course the boom factor of a compressed explosive gas in the engine compartment. It does has the potential to make car crashes look more like the do in the movies though.