Tis the season for multiple A/C questions here in the northern hemisphere. I have one as well. My early build 1994 is (I believe) an R12 system. I'm pretty sure I've eliminated all the blower/control problems. However, it blows warm air instead of cold. What do I need to watch for when I take it to someone? Do folks still work on R12 A/C's?

TIA,
Tony

FYI: I'm a blathering idiot when I comes to a/c issues

 

Hard to find a shop that deals with R12. There may not be any left at all.

When I left the repair business in 2008 R12 was still available but *very* expensive, so much so that many shops simply stopped using it altogether.

Cheers
DD

 

So how hard/expensive is it to upgrade it to an R134a system?

 

The 134A system was introduced in 1990, your car should be 134A. If not you will have to convert it to 134A as R12 is cost prohibitive and requires special permits to use. Not a hard conversion as Jags used GM A/C units.

 

I read in another thread that you tell R134a systems because they use schraeder valves - is this correct?

 

Both R12 systems and R134a systems use Schrader valves, but different sizes.

Cheers
DD

 

Well, sort of.

I recall that the provisions of the Montreal Accord (or whatever it was called) were enacted into law in 1990. The phase-in to R134a was gradual and manufacturers had until 1995 to comply. Some did so ahead of time.



If you're referring to the compressors, yes, for ages and ages Jaguar used the GM/Harrison "A6" compressors. A '94 might well have the Sanden-type compressor. Not sure exactly when the GM compressors were dropped. My '95 doesnt have one.

Cheers
DD

 

Depends who you talk to

Some merely evacuate the R12, replace the receiver-drier, refill with R134a, and go merrily on their way will good results. The operating pressures usually need to be altered for the 134a and some report the R134a conversions are not as cold. There are variables at play here

Other also replace all of the system o-rings to the type compatible with R134a.

Others still install all new hoses, as the R134a molecules are smaller and theoreticallt require "barrier hoses" to keep the molecules form slipping through . I know this step is often skipped as it gets quite costly.

Cheers
DD

 

R12 is still available south of the border. However, a full system conversion is the best way to go. Unless you plan to cut the car loose in the near future... I would strongly recommend changing out the o-ring seals - not very pricey if DIY. Most of the hoses can be obtained aftermarket...

 

As DD stated, there are various amounts of stuff you can replace, it just depends on how often you want to top it back off. Since the r134a molecules are smaller they will leak at o rings and hoses, so you can replace them with r134a proof ones. If you don't replace them at worse you will probably have to top off every summer with a can of r134a. No big deal since it is cheap stuff. When I converted my buddies miata and my xj6, I did everything and 4 years later on the xj6 I have not needed to put another can in it.