1994 - A/C conversion from R12 to R134a
 

Been searching throug the forum and read a good 200 pages of stuff on A/C conversion from the obsolete R12 to R134a.

The question that really interests me now is:

Should I try to cleanup my existing A/C and change to R134a by replacing accumulator/dryer and flushing expansion and the other system components, then leak test (pressure test or vacuum test) and then have it refilled at my A/C store with R134a?

Or would it be best to just invest 500 $ and buy new compressor, hoses, accu/dryer, expansion/intercooler, switches and valves and change the whole?

What experiences have members made with conversions / retrofit kits and stuff?

I'm willing to spend a bit of money and I'm able to do the work. It's just that a whole A/C assy (compressor, hoses etc. sits in my garage from a junkyard Blazer same exact model and year). So I have access to a full A/C system on my workbench.

Compressor unfortunately is a R4 type for R12. My research has shown that GM and A/C shops do not recommend a retrofit to this compressor.

And finally. Where is a good place to buy the whole stuff?

Thanks for sharing your experience and know-how.

Mark

The R4 compressor leaves a lot to be desired, and not a good candidate for an R134a retro fit. Have you considered R12a refrigerant? Considerably lower head pressures than R134a, which would help the R4. Google search is your friend ;)

Thanks, that was also my thought. As the compressor has already some 170k miles on I will have to rebuild it anyways. The problem is that R12 and R12a are completely banned in Europe. No way to come by it. So I'll change everything to R134a.

As the R12 is completely gone anyways I'll pressure check all my components and look for a new compressor and switches. Should work with an AC Delco or such R4 for R134a. Trying to do a mix and match to keep condensor and expander etc. but in the worst case if I have to start replacing hoses etc. I'll change everything.

As I'm willing to invest up to 750$ I should be able to get by all the parts at Rockauto or one of the A/C dealers.

Might want to explore an alternate compressor manufacturer. The Harrison HT6, (used on 2nd gen Blazers) has a "less than stellar" reputation too. Sanden makes a great plug and play compressor to replace the HT6, they might also make one that replaces the R4.

Thanks for the advice - i'll take it!

Seems to be a PITA to figure what can be retained as the joints and parts also do not really mix and match.
I'll start out by checking all my parts especially the condenser and expansion as they have to fit into the existing housings whereas the remainder of parts may be relocated in the engine bay.

Let's see with what I can come up - then I'll post it in "builds".