A/c Dead

Hi all

Not that urgent because i wont be sorting it out untill the weather warms up a bit but my A/C has packed up.
I have two problems i think, the first is simple, the compressor does not cut in only the fans come on when i press the A/C button, am i right in thinking that this will just be a relay? the other is that i get no cooling at all when it did work and i have been noticing greasy spots on the windscreen just above the demister vents for some time.
I did have the system regased in 2006 and it was converted to the new gas then R134? so what do you think?

Regards
D

Hi Dean

If the aircon clutch does not cut in this is often due to low gas pressure. The pressure sensor is there to stop the compressor killing itself by running without system pressure. Depending on how good the system seals are you can be lucky and hardly loose any gas over 5 or so years. Typically 2 to 3 years is more usual. Dropping pressure equals reduced cooling but because it usually happens very slowly you do not notice until one day something causes you to think about it or it drops so much it cuts out. The compressor has a simple 2 wire 12 volt supply with a plug joint so you can easily rig a temporary feed to force the compressor to work to check it out. If the compressor is visible then it is fairly easy to see if just the outside of the clutch is running (airconoff) or if the centre is rotating as well (compressor running). As far as aircon temperatures are concerned R134A gas does not cool as well as R12. This is actually a plus point as R12 was capable of freezing enough to form ice on the condensor which in an XM is alongside the heater element under the central dash. One of the causes of short life of heater elements and aircon condensers in the early XM's until Citroen changed production to R134A with the Mid-life Mk1 facelift in late 1992.
The grease spots on the inside of the windscreen usually indicate that the heater element has a minute pinhole and is glycol condensing from the leaking anti-freeze coolant. Possible but less likely it is compressor oil from a pinhole in the aircon condensor. Changing that is a dash out job as Shane showed in his photos a while back.

Hope it turns out easy.

Edit note: When your aircon was converted to R134A were the seals changed? as Citroen do a conversion seal kit and claim that R134A gas is not compatible with R12 seals.

John

This post has been edited by xmexclusive on December 28, 2008 12:50 pm

Hi Dean

If the budget will run to it, I'd get the aircon sorted sooner rather than later -- reason being that the seals in the system can dry out and fail with lack of use. While now it may have given up because of a tiny gas escape that's taken years, if a seal properly dries out, you'll have it regassed and it will be gone again in no time. Any air-con specialist worth their salt will tell you whether you have a leak of any consequence as they should put a high vacum on the system in the first instance and see if it will hold it. Smaller, long term leaks can be dye tested.
Don't forget as well, that having the air con functioning markedly reduces misting up and misting clearance in the winter (dries the air).

Mike.

Hi John

It would be very unlikely that the seals where replaced, it was just the drier i think, my heater matrix is only a year or so old so i dont think it could be that, but i would rather have to put a new matrix in than a condensor!
I will check the clutch wiring soon to see if it is electrical or pressure related then first and maybe get it booked in to see where its leaking as 2 1/2 years till the system is totally flat seems a bit quick to me.

Thanks
D

They seem to corrode out the evaporator unfortunatly. It's a MAJOR, major job to swap the evaporator. I'd put it on par with pulling and engine and swapping the clutch... Only pulling the engine and swapping the clutch would probably be quicker and more simple.

Why on earth would you change it over to 134a ?? Just dump a hydrocarbon refrigerant in it. they are as efficient and cool as well as R12 !! (and there cheap). The XM here is running HR12 (hychill -30). It works very well, even blasting quantities of cold air from the rear passenger vents.

seeya,
Shane L.

Good ol EU legislation thats why, it is illegal to use R12 now and many garages arent equiped to deal with the R12 gas.
I have to admit i hadnt heard of a condenser failing untill yours went, but knowing the XM i may well be getting to know my dash more than i would like to

D

Good ol EU legislation thats why, it is illegal to use R12 now and many garages arent equiped to deal with the R12 gas.
I have to admit i hadnt heard of a condenser failing untill yours went, but knowing the XM i may well be getting to know my dash more than i would like to

D

Nah, HR12 .. Not R12 It's basically just a propane/butane mix of hydrocarbon gases that emulate the cooling capacity and efficiency of R12 !

http://www.hychill.com.au/

it's probably sold as a "green" gas most places.

seeya,
Shane L.

Interesting, may look into that if it has a better cooling than 134 thanks.

D

QUOTE: Xmexeclusive: One of the causes of short life of heater elements and aircon condensers in the early XM's until Citroen changed production to R134A with the Mid-life Mk1 facelift in late 1992.



John..

Mk.1 Cars DID NOT Get R134 systems at all... Citroen DID NOT Put the R134 system in untill Series Two Cars...thats 1995 onwards....

Im sure I've mentioned this before.. but can prove it as I know of a 1994 L S1.5 SEi car with an R12 system...

Rgds
Paul

This post has been edited by citroenxm on December 28, 2008 10:08 pm

strange considering post 93 cars where no longer allowed to have R12 filled systems by law, and the R12 gas was no longer available for sale after December 95 either apparently.

D

Well, the year was a guess BUT I KNOW for a FACT that R134 did NOT come to the XM untill Series Two cars....

Prehaps S2 cars IN FRANCE started in 1993 but didn't get to us till 1994...

UNLESS - I will hold my hands up if someone has a SERIES 1.5 M reg car WITH Air con, factory fitted R134a...

Like I said thought, I ve friends with an L reg SEi with R12...

The mind wonders further...

Rgds
Paul

strange indeed, could be that cars produced after 93 had to have 134a rather than cars sold so your friends car could have sat around a bit like so many did before being registered in 94??
Or they could have been a bit lax regarding enforcement of the, then new law, who knows.

D

Ill get the RP number from the shell, and see what actual year it was built..

Rgds
Paul

Thinking about it i think i will stay with 134a, having a a/c system pressurised with propane may not be too much of a good idea when mixed with the electrical systems of a petrol engine in the event of an accident.

D

Hi All

Factory cut over date from R12 to R134A was actually 01/09/93 so the final years worth of Mk1 production and all Mk2's got the R134A fittings. I knew that I had recovered R134A bits from a scrap Mk1 as well as Mk2's.

John