AC converting back to r12

[Ryan]

Looking at a car. Not much history on the car but the compressor was replaced and a few other part about 5 years ago. It was charged but now does not blow cold. Obviously a leak. Since the system is kinda new, should I stick with the r134 or back to the r12? I see the adapter couplings on the hi and lo side. Dont know a lot about ac but is the big difference between the two systems is an upgraded Compressor? Or is it a completely different system all together? Is it possible to upgrade the compressor (if available) and run 134 and cool like r12? What I know for sure is the hi and low orifices are the original gn style since they have the adapters on them.

Also....what is the deal with these r12 replacements you see on ebay like freeze 12?

 

[Daniel PErkins]

Ryan-- my suggestion here is to stay with r134a ---mainly because unless you were a real smartie back about 10 years ago and hoarded a huge supply of r12--why put something into the system you can't get. R134a is what the industry is currently using. The stuff works fine at a little higher pressures, less amount in the system. The stuff they are selling as substitutes to r134a such as some propane or methane types you should stay away from--mainly because it is dangerous and flammable around a flame. Thanks. Dp

 

[Ryan]

Had a 93 chevy truck converted many years ago......not bad but was only cool at highway speed.

 

[Jay J]

We converted the wife's T over (to R-134A)and it never worked. We do live in the desert Southwest, FWTW. Converted it back to R-12, which fortunately we did put away some while it was still semi reasonable in cost. Another case of Gov't f-ing with our lives----toilets, light bulbs, oops, sorry for the rant..

 

[rob j]

I'd stick with R-12. Converting to R-134A on an older system designed for R-12 never cools like it did with R-134A. 7-10 years ago it was almost impossible to get R-12, and it was very expensive. Not the case these days. It is easy to get, and not nearly as expensive as it was a few years ago. No need to convert IMO.

 

[Jerryl]

I'd stick with R-12. Converting to R-134A on an older system designed for R-12 never cools like it did with R-134A. . . . . .

X2, been there done that.

OP, I am no expert, but 134A can work ok, IF the condenser is correctly sized. It still requires relatively much higher pressures because of it's lesser efficiency.

When ambient temps start getting into the lower 90F's, all bets are off, and R12 will provide much better cooling. System design, operating conditions dictate which one to use.

Ps:
Any swap will require complete flush, correct oil, orifice ajustment, and new dryer.

Good luck.

 

[6cylboost]

134a runs a higher head. In the refrigeration world, requires a slightly bigger condenser. On a conversion to 134a, your unable to get rid of all the heat in the condenser which was pulled from interior of car. Higher head pressure normally means higher suction. ( This just simply means a warmer discharge temp coming from your vents.) If 12 is available to you and you fix your leaks, by all means go back. If you plan on topping off, cut your losses and stick with134a. R12 is like a detergent but uses mineral oil. R134 uses a synthetic (polyester oil) which is created from a fatty acid. Its wanting to absorb moister and must be treated with care. It doesnt play nice and should never be exposed to the atmosphere. Pour some poly in a coffee cup and set it on the work bench and watch what happens. This is just my personal rule but I would run 12 on poly but wouldnt try to run 134 on mineral.

 

[6cylboost]

X2, been there done that.

OP, I am no expert, but 134A can work ok, IF the condenser is correctly sized. It still requires relatively much higher pressures because of it's lesser efficiency.

When ambient temps start getting into the lower 90F's, all bets are off, and R12 will provide much better cooling. System design, operating conditions dictate which one to use.

Ps:
Any swap will require complete flush, correct oil, orifice ajustment, and new dryer.

Good luck.

more eff hence higher head

 

[Ryan]

Looks like it has one of those off the shelf fitting adapters. Can they be taken off? I put one on another car a while back and it looked like it had some kind of locktit in it.

 

[Ryan]

How much freon goes into our cars? Not sure how big those standard r12 bottles are. If I remember they are smaller than the 134 cans they have now. May be able to find a few cans here and there, just need to know how much to get.

 

[aminga]

How much freon goes into our cars? Not sure how big those standard r12 bottles are. If I remember they are smaller than the 134 cans they have now. May be able to find a few cans here and there, just need to know how much to get.

3.25 lbs (it's printed on the AC lable)

But you should never charge by weight, always go by the gauges.

 

[Ryan]

So 5 cans?

 

[aminga]

So 5 cans?

Depends on the size of the cans

 

[TexasT]

I've been reading up and have been stocking up when I go to big lots. I just have to save up for a set of gauges n a vacuum pump. Then I'm gonna try it.
http://www.ihadav8.com/forum/index.php?topic=4082.0

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