Conversion of 91 EB A/C to R134a | Ford Explorer Forums - Serious Explorations

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Conversion of 91 EB A/C to R134a


March 24, 2000
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City, State
Deatsville AL
Year, Model & Trim Level
93 Ranger XLT
I am considering converting my 91 EB's A/C from R-12 to R134a. Has anyone done this? If so, tell me your experiences. The price of R-12 is ridiculous. Thanks

91 Explorer, Eddie Bauer 4X4

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Started to...until I saw the price. Just the kit to convert it (fittings, etc) was around $50 and that didn't include the gas. Stick with my R 12 for now.

91 XLT 4x4

You're just jealous because the voices only talk to me.

I did the conversion on my Explorer while my parents still ownde it. The compressor was leaking and needed replacement so we decided to convert it at the same time. The swap is stright foward. Remember to flush the condenser, hoses, and evaporator. You need to replace all the o-rings, the reciver/dryer, the orifus tube, and the oil. The only problem we have with the system is an untraceable leak. Its a slow leak and we need to top the freon off aprox. every 2-3 weeks during the summer.

Mr. Boyle, what it the approximate cost of the conversion. I know the coolant isn't cheap compared to R12. How does it cool? I guess it's better than what I have now...ZIP. Thanks

I don't recall the actuall cost. I did all the labor myself so that saved a lot. If I remember right the o-ring kit and oil was somewhere around $30, the reciver/drier was around $45, the orifus tube is around $6 and a rebuild compresser is around $130. These numbers may be way off as I did this over three years ago. The Freon is actually one of the cheapest parts at $8 a can. The system only needs two cans of R-134A compared to three R-12. As far as cooling goes it does just as good as the system did with R-12. The bigest difference is that the 134A does not cool as well at idle, it only works good when the vehicle is in motion.

I swapped mine from the R12 to the 134A when my condenser went bad and started leaking. The swap is straight forward and easy to do yourself. You can get all of the parts you need from autozone in a kit form. Just tell them that you are switching from the R12 to the 134A and they will sell you the right kit. I don't remember what the cost was for the kit though. But the plus side is that once you get it switched over you can charge the system yourself and you will not have to pay a mechanic to do it for you. Good Luck!

Happy Trails!
'93 XLT 4x4
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Gentlemen, thanks for the replies. I think I am going to go for the conversion. I am moving to Las Vegas and I hear that it is HOTTTTTTTTTTTT!!!! there. Have a good one

Thanks for all this info. My A/C hasn't worked in two years and I paid $150 to try and repair it and stupid frickin' good year couldn't do it! They still charged me of course } Dead Link Removed

I hadn't even thought of converting to R134a, but if it is only $200 I am going to have to seriously consider it. It would definitely be helpful for my road trip to Cali this summer.
Thanks again!

1992 Ford Explorer XLT
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Me too. Check out my web page.

Just thought I would mention that I have been converting all my vehicles to 134. I don't change any o rings or do anything but vacumn out the system for about a half hour and fill her back up with 134. Haven't had a problem yet and they cool just fine. Buy the 134 at Sam's club for a little over 3 bucks a can. Buy a low side fitting and a deal that fits the cans with a hose to put the stuff in and thats all you need. Total cost for one vehicle is probably 20 bucks and the next ones cost you about 12. Thats what I do anyway and it works for me.

I'm doing mine this weekend. My hoses are leaking oil at the crimps, and it's not cooling like it use to. I will be converting to 134a. Today I bought a new accumulator/dryer, orings, orifice tube, oil, schrader valve adapters, and some solvent for flushing out the system, all for $75.63. I tore into it today, removed the hoses, accumulator/dryer, orifice tube, and old orings. Flushed the evaporator and condenser with the solvent to get the old oil and crud out. The compressor won't need flushing. Tomorrow I will get new hoses made, some cans of 134a and whatever else I will need to finish the job. More to come.

what are you guys talking about? i know you are talking about something that has to do w/the a/c but what is r12 and that other one?

'93 explorer sport 4x4

Well, having a '93 you probably still have the famous R12 freon in your truck's A/C system. R12 has been baned a few years ago and is now very hard to find and of course very, very expensive. New freon, called R134a used in todays modern car's A/C systems was introduced to Explorers sometime in 1994 (at least that's how much I know). Main difference between the two is that R12 was not environmentaly friendly (something to do with the ozone layer) where the new stuff R134a is OK, at least for now. Who knows what the "magicians" come-up with within the next few years. Freon is the stuff that fills the entire tubbing and everything else called A/C system and once it's compresed it gets very cold and that's how you get cold air in you car in summer. I guess, this is the easiest way of explaining it. As I said R12 is hard come by these days and that's why most people convert to the new stuff to make thir life easier when the time comes of refilling the system. AS TO ANY LEAKS YOU GUYS MIGHT HAVE IN THE A/C SYTEMS!!!! I saw the other day at Pep Boys something like a can of R134a freon with red dye in it so it's a lot easier to detect leaks using this stuff. Try it, worked for me before.

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Andre Hryn
94 Limited

It is my understanding that R12 is no longer manufactured in the United States. However, it was (and probably still is) being manufactured outside the US. Because of the high price of R12 in the US, it is being brought into the US without permission (i.e. smuggled in). I have heard that just across the border north of Wash. State one can get R12 for much less than in US. Our Canadian friends might comment on this. Yes, I still have R12 in my 91 Explorer XLT and the AC system has been sickly for years (replaced compressor, etc.). I surely would like to get a "good fix" on this. By the way, these heat-pump systems are very simple and in no way should be as expensive and screwed up as they are in these vehicles (same heat-pump system or similar system that is in a refrigerator).
Mike in Seattle

oh well, it cools, and that's all i care about. if it fails and i have no money the windows always come down Dead Link Removed

'93 explorer sport 4x4

I was involved with the refrigeration industry when the Montreal Protocol was adapted. R-12 breaks down in U-V to release Chlorine. The chlorine consumes the ozone that is like sunglasses for the entire earth. There are many arguments both ways and a lot of politics on this issue.

R-12 can only be used in developing nations in new installations. Halide refrigerants are not allowed in new installations in the developed nations, US, Canada, etc. R-12 is allowed in some areas to the south though.

Having some understanding of the issue, I highly recommend the conversion to R-134a in vehicles.

The issues
* r-134a is a smaller molecule, it will leak where R-12 dosen't.
* r-134a requires a higher pressure to function, systems will need to be stronger, compressors in particular.
* r-134a reacts with r-12 to form an acid that will eat up a system.
* r-134a will attack some elastomers (O'rings) causing them to fail.

To perform a retrofit the least one should do is replace the compressor, replace the drier, preplace the hoses, and the orifice tube or expansion valve.

A retrofit r-134a in a r-12 condensor and evaporator will not cool as well. The evaporator needs to be slightly larger. The condensor will run at a much higher pressure.

The compressor oil from an r-12 system will gum up the works when exposed to r-134a. Make sure you flush the system out well. My final flush was propane. -- BE CAREFUL!!!! PLEASE!

Talk to a reputable refrigeration man, many will fill in the details.

'91 stock 4X4
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Based on above discussions, I have the following questions:

- Can any of the Explorer R134 system components be retrofitted to the R-12 systems such as evaporator, etc.?

- Are there any good manuals out there that go into sufficient detail to allow a "shadetree" to accomplish the retrofit in a competent manner? (Assuming he has the right tools available)

- Are all rebuilt compressors built to use R134 or something other than R12? Do you have to specify this when buying?

RD1991XLT, Yes, the evaporator and the condensor can be used. The other components should be replaced when there is a possibility of the r-12 contaminating the r-134a or the oil.

The evaporator and condensor will run at a higher pressure and the cooling will be slightly less, but acceptable... I live in the humidity capitol of the world, Houston. Mine does okay in August and September - the hottest days of the year. It does't cool as quickly in short runs, but fifteen or more minutes, it is fine.

If your system has already lost its charge, a shade tree mechanic can do the retrofit. If the unit has not lost it's charge, please have it recovered by a reputable A/C guy. Some are pretty nice and will guide you.

BTW there are schroeder valve conversions for adapting the filling valves to the larger r-134a. DO NOT USE A SET OF R-12 GAUGES TO SET UP A R-134a SYSTEM!!!!!!!

Your local library may have the books you need for reference.

Let me know if you have any more questions.


Thanks for the information. Thankfully, my '91 Explorer's a/c is still running well on the factory (untouched) charge of R-12. But, that could change any day. I don't plan to mess with it 'til it dies, just looking for alternatives when it does.