Mechanics

CHEVY CHANGING FROM R12 FREON TO 134A

1991 Chevrolet S-10

Air Conditioning problem
1991 Chevy S-10 6 cyl Two Wheel Drive Automatic

I was going to change my freon from r12 to 134a. I called a local mechanic about doing this and he told me if I did that I would have to replace the accumulator and dryer. He said if I didn't that I would regret it later. I watched some videos about this on you tube and they all said that there was a fitting on the low side that would have to be replaced (comes in a kit) but nothing about replacing parts on the air conditioner. Is this true or is he just trying to make a few extra bucks off of me?
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Bodeen82
December 10, 2008.




The proper way to do this is to recover any R-12 left in the system. Disconnect ALL the lines and flush the parts with solvent to remove any excess oil. Then replace the drier, and accumulator. Also you may need different pressure switches depending on which compressor you have.
Personally I would replace the compressor with one that is rated for 134A (many available that work with both and are bolt ons)

Then you install the conversion fittings and charge the system using pressure gauges and temperature. You should end up with a charge of approximately 75-80 percent of the amount of R-12

If the system has leaked down the 134 will leak down faster. So replace/repair the leaking part.

DON'T use one of those death kits you find in many parts stores without following the above. The ones that claim you just swap the fittings and add the 134A and you're done. They tend to cause more problems and compressor failure.

If done correctly the system will work and keep you cool. Do it the shortcut way and at best it may work halfway, at worst you can watch the compressor die quick.

Tiny
SWilliams
Dec 12, 2008.
Thanks for your advice! Apparently my mechanic was correct and not trying to rip me off. I went to the autoacforum that was at the bottom of your post and found a accumulator-drier for 16.00. So this is all the parts that I would need? If not could you give a list of everything that I would need. Also my mechanic said he could put in freeze12 instead of the 134a conversion. Do you think that this would work and would I need to replace anything to do this? He said that he would check for leaks first and repair what needed to be fixed. Thank You very much for your advice! I think you saved me some money and aggrevation by jumping in and just doing the freon swap. Thanks again!

Tiny
Bodeen82
Dec 13, 2008.
I would use the 134A. Mainly because of the ability of others to work on it if you have a problem. Freeze 12 is a blend of 80% R-134A and 20% HCFC-142 as a blend it is not able to be recovered by current EPA standards. Also the 134A is cheaper than the Freeze 12 and will work as well or better. One thing you may want to look into since you need to replace a few parts anyway you may want to change the condensor to a larger 134A friendly unit. One from a later S series with 134A should bolt in without much work.
Parts wise the drier, replacement O rings and the condenser (if you wanted to replace it) plus the refrigerant and proper oil. If you're handy with a wrench you could do a lot of the work yourself.

Tiny
SWilliams
Dec 14, 2008.
What parts from a later s10 could I get from a junkyard to make this conversion work and which ones should I purchase new. I have a friend that owns a junkyard and could get the parts for a little of nothing. I have some mechanical abilities but I know nothing about air conditioning. Any suggestions on forums that I could go to to gain a little knowledge. Thanks Again!

Tiny
Bodeen82
Dec 14, 2008.
Well if you have parts access you could grab a complete system off a 94 up P/U or 95 up S- Blazer. That would get you the correct hoses, condenser and brackets. I would probably grab the A/C compressor brackets and hardware to swap as well. Get it all bolted on and you would have a 134A system, if you grab it off a vehicle that is still holding a charge and cap the fittings ASAP it would make less work for you. You still will want new Orifice tube, O-rings, drier, because you really should replace them if you open the system and DEFINITELY if your switching refrigerants and not replacing the evaporator. The rest you could get from the donor vehicle. I'm not 100% sure but I think the evaporator core would even bolt in as well, It's a bit of work but if it's a vehicle you wanted to save it would be worth it to have the matched hardware instead of mix/match stuff.

. Just ask questions and we will point you to the knowledge.
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Tiny
SWilliams
Dec 14, 2008.

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