Motor Vehicle Maintenance & Repair Stack Exchange is a question and answer site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have an older vehicle that has AC, but it needs a recharge. It uses the older R12 refrigerant and it is very expensive and can be difficult to locate as it is not made in the US anymore. How do I convert it over to cheaper newer R134a? Can this be done without replacing the AC compressor?

share|improve this question
I haven't done this, but a little surfing finds: – Peter K. Mar 12 '11 at 19:28
It might depend on the vehicle. Can you be more specific? For instance, my mechanic told me that my 1992 Volvo 940 would need a new evaporator and condensor in order to use R134a. – William Cline Mar 14 '11 at 16:05
up vote 3 down vote accepted

Checkout the Auto AC board at AC Source

There are some good people on there.

Don's right. You do need to flush the old oil out of the system because they don't mix. Also it's difficult to flush the compressor so odds are it will not last i you don't replace it. The best thing to do is change the compressor out if its older at the same time, replacing all the o-rings too. R134 operates at higher pressures and it won't be as efficient, so you have to be careful not to overcharge. Older condensors designed for R12 might not cut it.

share|improve this answer

I have done it before. I just replaced all the seals and o-rings, cleaned out all of the old oil and then refilled with r-134a. That's about it. I did it on an '86 Volvo 740 and it worked really well.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.