A/C convert

90redsc

Registered User
90 XR7, My A/C is out. I have replaced the condenser, dryer, compressor. nothing in the system. What do I need to do to convert to a 134 system.?new compressor is not hooked up at this time.
 
I am going thru this right now on my 89 XR-7,

This is what I have done, change the drier, change the condenser and the liquid line.Now you need to make sure your system is emptied of the mineral oil from the R12. What you should do is have the system checked for leaks and flushed.Once you know all is well have it filled with 134 and make sure they put the compatible 134 oil in it.Its very important not to mix the oils,you will need to put the 134 quick connect fittings on it as well( Red and Blue caps), these fit over the existing high and low side servicing ports.
Also make sure you change the o-rings, spring locks and the most important thing to change is the accumulator/drier
 
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There is some off the shelf brands at Auto Part Shops, I have seen them at NAPA, but I think the best way is to take it somewhere, I think there is a machine that can flush it and then do a Vacuum leak test.
 
all this should be done, but is not necessary. have a shop suck the old fluid out put a vacuum on it, have them fill it will the proper amount of oil needed to the a/c compressor, add dye and proper 134 fittings and go from there and then if you do have leaks which you may after so many years you will have the dye in there and know where it is coming from. basically just go to the shop and tell them you want to retrofit your car, and thats what they will do. or just replaced all the parts in the system first if you want...good idea...not necessary.

removing the old fluid and creating a vacuum should get nearly everything out


I am going thru this right now on my 89 XR-7,

This is what I have done, change the drier, change the condenser and the liquid line.Now you need to make sure your system is emptied of the mineral oil from the R12. What you should do is have the system checked for leaks and flushed.Once you know all is well have it filled with 134 and make sure they put the compatible 134 oil in it.Its very important not to mix the oils,you will need to put the 134 quick connect fittings on it as well( Red and Blue caps), these fit over the existing high and low side servicing ports.
Also make sure you change the o-rings, spring locks and the most important thing to change is the accumulator/drier
 
I just had my 89 SC done yesterday. Total flush, took all of the lines off and replaced all of the o-rings, pumped it down, reserviced, leak checked, and topped off. $438 parts and labor.
 
Thanks guys for the advice. In addition thanks to all that helped with the P/S line replacement...Got it done but it was one pain..
Thanks again
 
Why do you want to convert to R134a ? R12 goes for $20 a can, everyday on *bay. Cools better than R134a, in systems designed for R12.

Also, I wouldn't use those flamable (freeze 12, I think) refridgerants in any car. Would you want propane/butane venting around/in your car, after a crash? (God forbid).
 
dont listen to this guy ^^ dont just try and fill it up with r12 have a shop retrofit it and be done. you will waste more time and money in buying little cans of that crap.
 
Thats what I said. I haven't had any experience with a/c and made my comments based on that....no i made them because I'm a genius.
 
IF you can find r12 (Brand name Freon), it will work better in your car.. hands down.. HOWEVER, many of us don't have a license to purchase, nor want to spend $$ to keep it up, so the decision to convert to r134a is the more economic choice. If done correctly, it will work adequately. Almost as good as the freon. :cool:
 
Walmart has the cheapest R134a, I have ever sceen, 9.99 can. *bay R12 $20 can plus shipping, typical. Most cars require you to open 3 cans.

I converted an my 85 Camaro to R134a. Installed new dryer, oil, orifrice and reman compressor. Didn't cool nearly as well as my 91 firebird, w/ R12. Same basic AC system.

your car, your $$. I'll go with the factory spec refridgerant.
 
I dont know;...I've 38-40 degree air coming out of my system.The correct amount of oil,refrigerant,a new R134A compatable condenser,and a clean system internally make a big difference.
 
Yes its $20 a can so you spend $60 for 3 cans then you wait for them to come at least a week for normal ebay items...then once you get the cans loaded into the system what if you have a leak...then you have to put more in with dye and then buy a florescent light to look for leaking dye. so you wait another week to get the cans theres another $60 plus the cost of the florescent light. for what....to save a couple of degrees??? maybe....on your camaro did you replaced every piece in the a/c system???? and did you flush the system and pull a vacuum on it? if not it could have had something to with the other parts to your a/c system that you did not replace. and not every ac system will cool the same even if its the same year car there are different variables you need to think about....parts go bad

if you go to a shop tell them to retrofit it add dye and check for leaks so if there is a leak after they fix it they will normally refill it again for free and you only pay to fix the part that is leaking...


Walmart has the cheapest R134a, I have ever sceen, 9.99 can. *bay R12 $20 can plus shipping, typical. Most cars require you to open 3 cans.

I converted an my 85 Camaro to R134a. Installed new dryer, oil, orifrice and reman compressor. Didn't cool nearly as well as my 91 firebird, w/ R12. Same basic AC system.
 
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listen up everyone despite what you know this is the truth


first you need to ditch the compressor and accumulator
condenser and coil can be kept but needs to be flushed
you can not flush lines... replace them all
fill new compressor with oil and mount it on car
be sure the oil says its compatible with r12 and r134a
connect all new lines which should have the r134a fitting already
run a vac on the system till you get to -30 microns,
shut off the vac and let it sit for at least 30 minutes
if it holds -30 for 30 min then time to fill it up
first put in the can of oil, make sure its r12 and r134a friendly
now about 3 cans of freon... dependent upon outside temps
jump off the low pressure sensor on the accumulator
do not jump off the clutch on the compressor thats just stupid
check your gauges while you fill it up
low pressure depends upon ambient temperature, it varies greatly
usually 45psi low pressure of r134a is about right on an 85 degree day


its always a good idea to mount an inline filter on the low pressure side so you know whats going on with your freon... sometimes after an r12 to r134a conversion you'll get build up known as 'black sludge' which will destroy a new compressor in no time!

hope this helps someone... i've done countless r12 to r134a swaps in my time and have yet to have any problems.
 
I am confused, you said fill the compressor with oil, then you said to fill the first can? Can you clear that up...my understanding is the 3.8 SC motor requires 8 oz of ester oil in the compressor... and thats all of the oil required for the AC system.Where am I mistaken?
Thanks
 
I am licended in auto air,when you bought your parts ,did you get a new low pressure switch,screws into the dryer.in my former dealings with a system that quit working the first thing people think is the compressor went bad.99% of the time the low pressure switch was bad,less than 5 dollars
 
I don't "wait a week for normal *bay shipping" of R12. I keep it in inventory, along with my stock of other lubricants and chemicals.

Of course I flushed the system first and pulled a " 30 inches of mercury" vacuum, for 1/2 half hour. Then sealed it off and observed absence of leaks, for another 1/2 hour. I did not replace the low pressure switch , probably should have. I no longer own the Camaro I mentioned.

All my other cars, that I have worked on and maintained thier R12 systems, typically blow close to 32 o F, and hold a charge for years. I also have several vehicles, with R134A designed systems, which cool just fine. (00 Ford Excursion w/ front and rear AC, 01 Corvette).
 
Walmart I converted an my 85 Camaro to R134a. Installed new dryer, oil, orifrice and reman compressor. Didn't cool nearly as well as my 91 firebird, w/ R12. Same basic AC system.
A redesigned condenser makes a big difference. I've tossed out at least 2 older tube&fin style OE R12 condensers and used either a 94+ model or aftermarket replacement. The newer ones have 6mm tubes with 2-3x more turns and shed a lot more heat. As garsc has said, the biggest factor in a retrofit is the condenser. I've found that to be true as well. Bear in mind, I live in a high heat state, so while some people further north have good results with the original condenser, its just too darn hot here.
 
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