Eric79-L48

Someone tells me that I can just evacuate the system, load R134 into my R12 system and everything will cool perfectly - but I also hear about people "converting their system to R134".

What's the real deal on this? Will my factory original R12 system take R134 and actually work assuming it works great with R12 today? Anyone?

Bob Onit

If it works great (no leaks) with the R12 then I would stay with it

I am no A/C expert by any means but I do know that the conversion requires more work than you have stated

R12 is VERY expensive unless your lucky enough to have access to some.

BarryK

usually R12 is pretty expensive when you can find it but it's well worth it - it cools better than R134 no matter what anyone tells you. Typically R12 will cool about 5º-7º cooler and on those hot & humid summer days and with the the inherently hot interiors Vettes have that difference in the cooling makes a difference in your comfort

If you decide to convert to R134 you can't simply evacuate the system and refil with R134. The R12 and R134 gases are not at all compatible and the all the O-rings need to be changed out, I believe the drier/accumulator needs to get replaced, and the oil needs to be changed because all of these things are contaiminated with the R12 gas.
When they say convert to R134 that's what it really means - system evacuated, parts replaced, system re-vacuum pressure tested and refilled with new oil and R134.
Typically will run about $250 which was the pricing given to me by a few local shops on the conversion.
I got lucky and got hold of a bunch of R12 so I was able to keep my system as is without needing to convert

Bob Onit

Ill be right over Barry
How do you take your coffee

SIXFOOTER

I been doin a little research on this and Yes, there are some changes that need to be done, nut just a vacuum and refill job.
New Seals
New Hoses depending on how old your car is, you need Barrier type hoses
New Drier
New Orifice tube
you need to flush the system with AC system flush to get ALL the old oil out, it must be clean. This includes the compressor, condensor, evaporator and lines.
THEN put it all back together with the new drier and orifice, vacuum down and leak test, fil with pag oil and r134a and your good.

...Roger...

Eric this is the correct way but it costs $$$$$$$$$$$$$$$$$$
Here is my take on it.I offer both ways to my customers,the big dollars way(correct way) or just converting using Wal Marts conversion kit which costs about $45.I give them the choice and the facts and talk over the worst that can happen which is -you'll have to go back and do it the right way-"possible" but not likely you could lose a compressor-stop up the condensor and or evaporator.All have chosen the conversion,around 40 of them over the years.Non of them(knock on wood)have had a problem due to the conversion.Vacumning the system is a must.Way out all the differances but if cant do it yourself it might be more economical to have 12 put back in.Just my 2 cents !

BarryK

cream and sugar.....

first, another forum member sold me at a reasonable price a few 12oz cans he had sitting around he didn't need anymore than I managed to get a 30lb cannister of R12 for the best price all all - FREE!
Since the '78 is the only car I have that requires R12 i should be set for a while I think.

carriljc

The first one I did everything, every o-ring, dryer, control vlv(this one had a control valve not orifice), cleaned out the system(everything), blew it out with air(everything), etc...only thing I did not do was replace the hoses. Installed charging/evacuation ports. Evacuated, recharged...turned out great.

Second one I replaced the dessicant dryer, readily accessible o-rings, and the orifice tube, cleaned out the condenser, blew it out with air; installed charging port adapter. Evacuated, recharged...turned out great.

Third one belonged to buddy of mine; replaced dryer, a couple of o-rings, didn't clean out anything, didn't blow it out with air, just installed a charging port adaptor, evacuated and rechared....turned out great.

4th one I assisted another friend of mine to do his. All he did was install charging/evacuation ports. Evacuated and recharged. Turned out great.

carriljc

and it uses R-134. Cools to 37 degrees at the center vent.

The other 4 vehicles I have played with all cooled to 40 degrees.... or lower.

noonie

If you must convert to 134a
The reason why most conversions don't work as well is because the coondenser was not changed to a large enough parallel flow type.
r12 has better heat release characteristics and therefore can use a much less efficient condenser.
134a will not work well with the original inefficient original condenser, but when upgraded to the proper condenser it will cool every bit as well as the original using r12.

Even though a new Honda 4cyl engine is a great engine, you wouldn't put it in your vette would you. Same thing. BTW, all the aftermarket systems like Vintage and Hot Rod don't use the original type condenser

It is a pain to install with fittings and pipes but it will work very well

jayr

I have done many conversions and some work better than others. Some condensers are better cooling on some models and some are not.
The 134R will create high temps at the condenser. Extra cooling is a
good idea, second fan , shouds, aftermarket fans but the best is a
R134 condenser. R134 does not cool as cold as R12. A conversion in
in the north country is more acceptable than lets say Fl. or Arizona. Never the less 134 I think is the way to go. You do not need to change
perfectly good hoses , seals, or a good working compressor. You do need the paxel oil, and do add an additional 6 to 8oz depending on size
and if you change accumulators, hoses and so forth. It its a compressor you have to prefill that with a certain amount depending on
compressor I have done about 20 with changing nothing but the fittings. I had a ford that leak a can of R12 a month and never leak a
drop after adding 134. I had some that didn't cool worth a damm until
going down the hwy at 65. If y9ur vette runs hot expect it that it could run even hotter unless you can keep the condenser cool. R134
runs at higher pressures than R12. Also a vacumn pump is really needed