My AC is apparently not blowing cold--something not very unexpected! But is there a way I can tell if it has already been converted from R12 to R134a?

If it hasn't, how hard would this conversion be?

 

Not sure about up there.

Down here the R12 had small "threaded" charge portals, with black plastic screw on dust caps almost the same as on the tyres.

The R134a have "clip on" larger portals with a Red and Blue cap. These charge portals are quite a bit larger than the older R12 system.

The older R12 system had glorified hose clamps on the "larger" suction hose fittings, as pressures were lower. The R134a hoses are ALL crimped, as pressures are higher.

As for retro-ing the system, you will need to talk to an a/c mob you trust to get it done.

Again, down here, most will not use that old black beast compressor, it is too unreliable at R134a pressures. Many here will differ, that is fine, but my older cars are all retro-ed with Sanden compressors fitted.

The hoses will need to be renewed. The TX valve "should" be replaced. The system "should" be flushed of the older style oil. The drier unit will need replacing.

I have never had to replace the condensor, or evaporator. As the pressures are higher, and the brain does click a tad about these pressures in the "old" components, but I have never had issues.

The airflow over the condensor is more important, so your fan clutch MUST be up to snuff.

As an example, our 2 V12's have the Sanden compressors, twin thermo electric fans, new TX valves, new driers, new hoses, and that was 10+ years ago, and still COLD. The old '64 S Type has been a/cond since 1992 when I fitted it. It is R134a, and runs a Toyota Corolla compressor, and is so sweet in 43c temps.

 

Thanks. Do you have a part number for this Sanden compressor?

How hard is it to replace all these hoses? Do I need to disassemble the dash? I also saw your FAQ on ac conversion and you mentioned modifying the mounting bracket. Could you explain this? Also will the accessory belt be the same and routed the same way? Thanks!

 

OK, I use a Sanden SD7H15 on the V12's, and 6cyl engines, and that is probably "old school" by now.

Have a look at "sanden.com" for all the variables.

The hoses are NOT hard, and any competent a/c guy can do it. It is NOT special because it is a Jag, and dont be told that, they are conning you, trust me.

Dash is NOT touched, NO hoses or valves in there that need your attention. The TX valve is at the firewall, alongside the heater tap, and if some idiot is not careful removing it, the pipe that goes inside the car will be broken, and then the dash MUST come out, be warned, but do not be scared. Common sense will NOT damage that pipe.

The bracket??, well some out of square thinking is all that is needed. The Jag bracket stays on the engine, it mounts the alternator from below, and we dont want to mess with that. The old comp is removed, along with all its brackets. Some simple angle iron duly cut and shaped, is attached to 2 of the mounting lugs of the Sanden (one at the front, the other at the rear), it is then placed onto the Jag bracket, line up the belt, ensuring it is running true and square, and the Jag bracket is duly marked, then checked again, and those 2 angle iron bits are welded to the Jag bracket. Refit the Sanden, attach the Jag adjuster bolt arrangement, and the original belt, or a new one would be nice.

I have done this 4 times, BUT, the engines were out of the cars, so it was easy access, and lining things up was simple. Doing it, "in the car" would be more awkward, but certainly not hard.

NO, I did not take Kodaks, and the cars are LONG gone, this was before I owned a digital camera. I have V12 Kodaks, but of NO use to 6 cyl application.

I always used the same belt, and adjuster, no changes at all.

 

Thanks for the info. Unfortunately this sounds like it's out of the realm of possibilities because I can't fabricate my own brackets.

Suppose I do want to keep the big old black horse Harrison A6 compressor. If I do convert it to r134a what sort of problems will I run into? You said it isn't reliable--do you mean that it starts to leak or something? I would have no problem with having to recharge it once a month or so in the summer as it is not going to be driven that often.

 

Again, not sure of things up there.

Down here we no longer have R12.

Most a/c mobs will not gas these old compressors, due to leakage and license issues with the legal types.

I once fitted a R134a spec "black beast" compressor to my V12, looooooong ago, and retroed the system. Lasted about a year and siezed, and exploded the clutch, which I then found this was a fairly common issue due to the R134a pressures.

My only suggestion would be to go and talk to a few a/c operators, and make the decision based on their advice. These compressors are dinosaurs in anyones language.

 

I guess what I'm taking away from this is that I will need a new aftermarket compressor for sure. I think I will talk with someone from a local Jaguar shop and maybe they can give me some ideas or help me fabricate the brackets if they have done it in the past.

 

I'm in south Florida so A/C is a must. When I got my 86 XJ6 I had know Idea what was in it but it didn't have enough of it to blow cold. All I did was hook up my cheap Harbor Freight manifold gauges and let out the what was there into a bottle. An open bottle won't recover the refrigerant but it keeps the oil mist off the floor. Then I used a $10 air vacuum pump and put the system under a vacuum. After that I filled it up with 134a and oil and have been driving like that for 2 years now. The air is very cold even on hot summer days. The only problem I have is it won't start with the air on but I don't think that has anything to do with the a/c because it also will stall sometimes with the power steering. That is why I'm here looking for a solution to my stalling at idle problem.

 

Thanks. Could you explain in a little bit more detail what the manifold gauges are, and where you hooked them up? How do I let out the refrigerant into a bottle? Also what sort of air vacuum pump are you using?

Thanks so much for your help!

 

Vacuum Pump with R134A and R12 Connectors

Is this the sort of vacuum pump you are talking about?

 

Alan,
Take a look at this thread by Joycesjag https://www.jaguarforums.com/forum/s...ics-faq-55219/ you can see all the bits and pieces. It's a different car but the same procedure.
You can rent the vacuum pumps from Autozone.

 

Thanks. I guess the first thing I need to do is establish whether or not the AC has been converted to r134a. Then I can determine from there what needs to be done. If it has been converted, can't I just keep putting r134a in (assuming it leaks out after a while)?

 

Hello Alan,
May I jump in here? been doing a lot of retro on jags over the last tweny years here,
I love that old A6 but most people dont it seems. it does take a few horses to drive it and it can be a leaky old thing but fits in nice with a Jag if you ask me. As far as the 134 question goes, the fitting are much larger as somebody has mentioned so if it doesnt look like your tire valve it is 134.
The Sanden is a good choice for replacement and if you pick the right one, there are many styles with different fittings it works out nicely, I might be able to help with a bracket, I may have something around the shop for you, I will check if you want.

 

In my experience if you properly vacuum the system (as in run vacuum on it for a minimum of 30 minutes) when you get old stuff out, drain the oil and recharge with about 70-80% the weight in R134 as was specified of R12 you'll be fine. Done it myself in several older R12 cars.

 

The vacuum pump is the one in the link above.

This weekend I will post a video because I can't even begin to describe the confusing hookup of the gauges because the adapters were backwards so I had to switch the hoses on the manifold gauges.

 

I took the adapters off of my car because they leaked a little. So if it has the adapters on it is probably 134a. If not it could be anything.

 

Well it doesn't appear to have adapters--it has those small fittings. Also doesn't have an r134a conversion sticker, so I'm guessing it hasn't been converted.

Does anyone perhaps have a step-by-step on how to convert this thing to r134a, keeping the Harrison A6 compressor?

 

You've got to be able to run vacuum on it to burn off all the contaminants and old refrigerant. Evacuate, install 134 fittings then vacuum for at least 30 minutes, drain the oil out of the compressor then re-charge to 70-80% of capacity and add oil. According to Alldata an 83 XJ6 holds 2.5lbs (1133 grams) of refrigerant. Charging with 134 I would add 1.75-2 lbs (793-900 grams). Oil capacity is 10oz. Assuming everything else is functional this should work for you.

 

Sounds like a plan, if it doesn't work you are only out the cost of the refrigerant and the vacuum pump rental. (If you can't get a free loan from Autozone)

 

Forgive my ignorance, but I'm not quite sure how to do any of these things as I have never worked on AC before.

How do i evacuate? (I think I can figure out how to install the 134 fittings).

How do I vacuum? How do I hook up the vacuum to the system?

How do I drain the compressor of its oil?

How do I add oil? Is it a separate product from the refrigerant and where does it go? Where can I buy it?

Thanks for helping! I am just completely clueless!