Best replacement for R12

There are a few older vehicles on the road running with R12. R134 is'nt a great replacement, but are there any superior to R401a (dupont MP39) for performance and changeover ease? I assume standard accumulators, expansion valves, etc. are suitable for this. Is it mandatory to switch over to alkylbenzene oil from mineral oil? 401a is not cheap. Is the cost difference from R12 too little to justify the possible additional labor?

Reply to
Optimum
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Try R414B and/or R416A With the proper valve adapters, oil and markers.

Reply to
Don Ocean

R12 is about $80 lb/retail.. That should make you insure that the system is leak free.

Reply to
Don Ocean

I got a jug of Icor Hot Shot (414b?) a couple years ago, that was supposed to replace R12, and also much higher heat transfer than 134a. Can't say for sure, I'm not sure I ever used the stuff.

I've heard tell of folks who use 409a in cars. Runs good and cold. No oil change, or other modifications.

Reply to
Stormin Mormon

With cars, I don't think there is anything "leak free". External drive compressors are usually leaky.

Reply to
Stormin Mormon

Where you get R-12 that cheap?? It costs me more than that *WHOLESALE*

Reply to
Steve

Ford used York rebuildable compressors for years and the Mopar compressor systems remain leak free for long perios of time. The old GM rotaries leaked about 15% per annum right from the factory. I have an older Chrysler minivan with dual air and it has not been touched in

200,000 miles. Which is unusual as the evaporators tend to break down and leak after about 7 to 8 years. Nasty job.. Have to drop the steering column on those. Honda's seldom are leakers also.. I don't know about the rest. I have replaced a crapper load of compressors, filter driers and metering devices on a lot of vehicles. My biggest and best pay are on Big all wheel-drive farm tractors. Those farmers will not work without their tunes and A/C. Most of those rigs have satellite computers to control fertilizing and seed setting by Landsat satellite. Power comfort seat also has to be in good operating condition. >
Reply to
Don Ocean

Its got a bit of propane in it and is not neutralized by other gases like hotshot is. Or at least that is the excuse I got making it illegal to use 409a in mobile units. Also there is no adapter or sticker for it for Automobiles. Hotshot12, R414b, 416A are all deemed legal with the prescribed adapters and the proper sticker. When you deal with Auto's you do need a 609 certification, except for 134A. You do need to change adapters and stickers when you convert an R12 unit to R134a. I don't recommend that change unless you change the metering, oil and high/low sensors. Expect seal problems if you don't get all the mineral oil out down the line. Usually at the damned compressor. I do some high test classics and they only get R12 after an extensive renewal of all possible leak components and seals.

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Reply to
Don Ocean

Change nothing and use R-406a... just requires you to install a couple port adapters and refrigerant stickers.

Reply to
KJPRO

Thanks for the info, on vehicles. Yes, if I was going up and down a field in a boring, monotonous pattern, I'd also like radio and AC. I'd also be thinking CB radio so I could keep in touch with home. Or chat with anyone who was on the band.

Reply to
Stormin Mormon

Don Ocean posted for all of us...

If they are planting beans do they have to fart to power the seat?

Reply to
Tekkie®

I had heard that 409 was not recommended for cars, but forgot the reason. Also, I seem to recall seeing a TP chart as well as a graph that compared it to 12. The graph had the temp horizontally and the pressure vertically. It seems to me that around 30 deg more or less, the 409 pressure was actually lower than that of 12, but as the temp increased, it got higher than 12. but the two lines stayed fairly close throughout the normal temp range found in refrigeration, but at a certain point the

409 line shot damn near straight up. I don't remember what that temp was, but it was well within the range of what you could expect to see on auto a/c. When I worked in refrigeration, we used a lot of 409 in ice machines and it worked great. It is not good for cars, or small cap tube systems. FWIW, I dumped two cans of Freeze 12 in my GMC the beginning of summer and it is still cooling great. The R4 comp is leaking some at the seal. I have a brand new --not rebuilt--comp that I'm going to have a friend install for me this winter and recharge it with 12.( He has a garage and owes me some favors) Last week I got two partial jugs of HotShot, along with a bunch of other misc stuff, from a guy who is retiring from a/c and ref service. I have never tried HotShot before, but have heard it is pretty good. Any comments welcome!
Reply to
lp13-30

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