www.jec.org.uk

With the demise of R12 I was wondering how many others are still running on R12? Mine is, and the system is working fine at the moment.
If you have had to change to another gas it would be of interest to many others I'm sure which gas you converted to, did you need a different expansion valve and if the system is still performing as well as before.
Pop

I have recently converted to 134a. Had to fit two new hoses anyway as they were porous and fitted a new compresor and dryer. Not quite as cold as R12 but adequate during the recent hot weather down here.
At least the system can now be topped up cheaply.

Hi,

Recently had my 3.6 XJ40 drained and regassed with R134A. No part changes, just had a very thorough drain of the system, and a recharge. System now works better than it has for a while.

Pop

I'm still running R12. What a marvelous substance when it comes to air-con! Just a pitty it wasn't previously treated with respect and we might not be in the situation we are today. Oh and yes it works fine with lots of lovely cool air.

As I understand it for my mate who is an expert, 134A is a drop in replacement and whilst not quite as efficient does get the job done.

Nick

RS24 here. Its a direct replacement for R12. No problems.

R12 is the best refrigerant divised, since the 1930's, but downright ozone-abusive. There's fridges and freezers all over the world still running on the stuff after 30 or more years and likely to for many years to come.

R134a is a close substitute, you are supposed to change the expansion valve for the best performance, but many people don't. You are also supposed to completely flush out all traces of the old mineral oil and replace it with R134a compatible oil, but there had been some people who didn't. Replacement compressors are not overly expensive (+ flush out debris from failed Cpr.) '134 condensers need to be considerably bigger than R12 ones for the same performance.

Drop-in R12 replacements are available (i.e. R-49), removes the need to flush out the old oil, the gas blend being able to dissolve the mineral oil and carry it back to the compresser. Gas blends can't be topped-up like R134a (and other single gas types) can be. With a blend, the whole lot has to come out and fresh charge put back. Blends are R4xx; single gases R1xx. I use R-406a + PAO68 oil myself.

Latest refrigerant to be considered in cars is CO2 gas! Don't try this at home

I converted my V12 to R134a this spring. My compressor needed changing anyway but I also got a kit from SNG Barratt consisting of new R134a specific expansion valve (needed so that corrrect low temp maintained in evaporator), a new set of O rings (old ones incompatible with new oil) and a new receiver/dryer. It also came with replacement ester oil as the old mineral oil is incompatible with the new gas. It's essential to get as much of the old oil out as possible. It has worked really well. Whilst its not as good as a modern car designed for R134a it's not bad! Kirby Palm's book (available as a free download on the net) gives a much fuller explanation.
Jaguar do a kit which has new compressor seals, oil,receiver/dryer, O rings and connector valves (but no expansion valve) - part no JLM11611.
Good luck!!

Can anyone recomend a good bloke for doing AC works? I am of thh assumption that mine is completely Donnald Duck'ed

5 years and not even a hint of vaguely cool air ..

The old girl had spent 10 years in storage (as had her owner, a long story) before i got her, and just about everything had leaked from her ...

(no rust mind you)

on an '82 HE located in London.

RS24 here. Its a direct replacement for R12. No problems.

RS 24 is the way ahead. 134A was the drop in bought in to replace R12 but that will be phased out in the future. Problem with 134A is it requires a synthetic oil where as R12 requires a mineral oil so to change over from 12 to 134A means a number of changes have to be made to the circuit components. People who have changed over to 134A have found their original seals perishing really quickly . RS 24 uses Mineral oil which does not react to R12 components.
Can't help in the London area but I do know of an AC engineer in Cornwall who will recover the fridge gas, pressure test the circuit for leaks (using nitrogen and a drop test), de-hydrate and re-charge with RS24 for about £80

John Diller,
My air con work forward of the bulkhead is done by MASONAIR near Swindon, who also do aircraft work, £45/hour I believe, they're very competant although not Jag specialists.
However, if your "flaps" are not working, your "air-con" could be fine, but the cold air cannot get into the car, now we enter the dark zone......
The control systems of XJS aircons still puzzle me, not least because what you read in the book is not neccessarily what you got...........
If your car has been stood up for that long I suspect the control system is completely seized and there is probably no gas in it anyway.
Time to get your credit card out............
DH Dove

< removed by Author, was off topic! >

I bought my XJRS from a bloke who said the aircon had not worked for 3 years. Fair enough, and it did not work for me either. A year in, I noticed wetness on some of the pipes on starting. Fearing a leak, I touched it to find out what was leaking. It was condensation - the aircon had suddenly kicked in and now delivers ice cold air. Anyone got a possible explanation?

When I bought my 3.6 many years ago it had many faults, including non-working AC. The (Harrison) compressor is driven by an electromagnetic clutch, although it was being energised, the plates were too far apart to pull together. A bit of adjustment and it has worked fine ever since.
In fact most of the faults I have cured over the years which would have been *terminal* to many cars, have proved to be easily and cheaply cured cured, mainly due to poor maintainence.
Don't you just love it when a plan comes together
Pop

Yes, thinking about it, the aircon kicked in after I had changed the spark plugs, lifting and tilting the compressor in time honoured fashion.

I guess this is what they call 'character' in a car?

I see Halfords are now selling air con products. Canisters appear to contain R134a gas, lubricant and leak sealer. There does not seem to be much warning about seeking professional advice. What would happen if you used one of these kits to recharge a system without knowing what you already had ? Is there some labelling under the bonnet to tell you what you are dealing with ? I have a car with no service history and non-existent cooling from the air con system !
Pete