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Old 08-20-2002, 03:01 PM
Registered User
Join Date: Aug 2001
Location: secret
Posts: 3,044
Unconversion from R134?

Anyone gone back to R12 after R134? I'm seriously considering it. 134 just doesn't get the job done in my 300E. It's will keep you from dying at highway speed, but once you stop you're "sweatin' to the oldies"!! What's involved in the undo?
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Old 08-20-2002, 03:42 PM
public enemy
Posts: n/a
I went back to R-12 after being very disapointed with R-134. I took it to the shop and they just evacuated the R-134 and filled it back with R-12. Thats all. They did not even change the dryer, they said that there was no need to. AC works back like a charm although i never use it even with 100 degrees outside. I just do not like AC, I prefer the outside breeze with an open window.
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Old 08-20-2002, 05:37 PM
engatwork's Avatar
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 11,878
pe - I'll bet that Chevelle can make alot of breeze
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Old 08-20-2002, 07:32 PM
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Join Date: Aug 2001
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So can my Falcon.... but it's a HOT breeze!!

Getting off the subject but.... I remember back in the sixties, if someone bought a car with A/C, the first thing we did was to cut the drive belt for the compressor. Horsepower was a terrible thing to waste!!:p :p
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Old 08-20-2002, 09:26 PM
Join Date: Dec 2001
Location: Southern California, U.S.A.
Posts: 8,508
I converted my 93 Nissan Quest to R134a, and I was so disappointed that I converted back to R12.

And all they did was evacuate the r134a and filled with R12.
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".
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Old 08-20-2002, 09:51 PM
it leaks, its german
Join Date: Mar 2002
Location: raleigh nc
Posts: 1,111
While your at it, make sure the recirc flap works! Afterall, spending $30.00 and pound for 12 and not getting colder air would suck.

Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.
Raleigh NC
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Old 08-20-2002, 11:50 PM
RSH RSH is offline
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Join Date: Jul 2002
Posts: 106

Iam the biggest fan of a properly running R-12 a/c system, since you have already converted to R-134a, there is another trick to try, either bleed off about 12oz of the R-134a or evacuate the system and recharge with all but about 12oz and top off the system with "Cooltop" alot of people are impressed with the performance difference, It cost's a bit more than R-134a but you will only need one can.
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Old 08-21-2002, 12:11 AM
public enemy
Posts: n/a
Jim, yeap the Chevelle makes plenty of breeze which is useful considering that is has no AC. I have been working a lot lately on my engine simulation Dyno and I am gonna soon drop some higher compression pistons in it and a bit more cam. I run the specs on my computer simulation Dyno and it predicts upwards of 600 HP. I am also gonna add Posi rear end, I think am gonna need it.
I want to run low 11s to maybe high 10s, so got some work to do. I will probably settle for low 11s, though, because I want to keep it totally sreetable, too.
Take care.
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Old 08-21-2002, 07:33 AM
Posts: n/a
I reverse converted my old Ford pickup because the York compressor couldn't handle the added pressure. I did not simply evacuate and recharge, I replaced the filter drier, the compressor (because it was shot,) thoroughly flushed and put in mineral oil.

I would not reverse convert without flushing and putting in the correct amount of mineral oil. Although Ester is said to be compatible, that does not mean it can be the primary oil in an R12 system.

I hope I don't start an alternate refrigerant holy war, but I would NOT use ANY alternative refrigerant other than 134. They are either blends or flammable. Flammable refrigerant is used a lot but illegal. Blends have their problems because if a leak begins, the individual components of the blends leak off at different rates necessitating complete recharge to get it right.

As Steve Brotherton has often pointed out, R12 is the least expensive component of your a/c system. You will be much happier with R12 rather than saving $30 or $40 on a miracle cure.

My $0.02,
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Old 08-21-2002, 08:57 AM
Registered Diesel Burner
Join Date: Aug 2001
Location: Northern Virginia
Posts: 2,911
I've got a very expensive professional conversion to R134A, as evidenced by the previous owner's receipts from the most expensive Mercedes dealer near DC. It cools adequately around here whether running along or standing still in traffic.

Last year DC had 16 days of summer weather exceeding 90 degrees. So far this year we've had 48, and its not over yet.

The R134A conversion, perfectly done, is not quite as cold as R-12. We had one day that was really really hot (100 officially) and I switched to internal air recirculation rather than taking in outside air in order to stay cool.

Considering my local climate, if the R-134A system fails somehow, I still won't go back to R-12.

Any evidence that the hole in the ozone is getting any SMALLER from all this effort to eliminate R-12?

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