XM Air Con

Post your Cit/Peu/Ren air conditioning queries or advice.

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sdabel
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XM Air Con

Post by sdabel » 16 Dec 2004, 04:31

The A/C in my 1996 XM 2.1 TD has been getting weaker and weaker over the last year. I took it into a local place, they regassed it with R134A and told me that the A/C valves had a small leak. So they replaced the valves. As I understand it these are the filling valves on the firewall. A/C worked when I collected car.
Two days later (Yesterday) the A/C is no longer cooling. I called today and it is going back next week. I am thinking that there must be some leak that is hard to detect. Any ideas where this might be?
regards from hot Adelaide
sean
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alan s
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Post by alan s » 16 Dec 2004, 07:49

Did this character do a conversion from R12 to the 134a?
If so did he fit the "O" rings and all the other stuff supposedly that has to be done? The reason I ask is that if it took 12 months to leak slowly before and after he's worked on it there's only a life expectancy of a couple of days, I suppose it's not rocket science that works out where the problem started.
On BXs the weak spot is the T/X valve but I don't know the type of system the XM has. On the BX, it's a case of whipping the glovebox out (about a dozen screws)and then there's a black plastic cover held on by 2 hex headed pks. Behind this you'll find the T/X which looks like a square block of metal with 4 copper pipes leading to it and a bellows on the top.
Leaks are easily seen in the form of oil leaks, and in the case i=of the BX not only are these usually visible on the act8ual T/X but also as a residue around the bottom hex headed screw and nearby area.
It is possible that this could be the "valve" he was referring to & knowing 12 volt sparkys as I do, they usually want the leak to be sitting right under their noses and seem to object to have to go looking for it.
If you find that's where the T/X is located, I'd suggest you remove the glovebox and shine a nice bright spotlight in there and have a close look around before you take it back to him. At the end of the day, the symptom sounds like either gas loss or even possibly moisture if he's been a bit gung ho when working on it.
Alan S
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sdabel
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Post by sdabel » 16 Dec 2004, 15:39

Thanks for the reply Alan. The car already had R134A in it when I got it and I assume that this was normal for a 1996 build car (UK delivery)?
Any advice on changing this to something else ? I had my CX regassed with hydrocarbon based gas (propane) and noticed big improvements in effectiveness.
As you point out they may have not looked very hard to find any leak. I was wondering if the leak only occurs at high preasure ? Meaning that the gas rapidly falls to a residual preasure ?
I don't know where the TX valve is but will have a look through the XM-L to see what I can find about removing gloveboxes.
regards
sean
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alan s
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Post by alan s » 16 Dec 2004, 16:37

Sean,
I don't know when they went 134a in the UK as each Country seems to have a different set of rules & regs, after all, they were still buying cars with no cats when the BX phased out in '94.
As far as high pressure leaks go, they would be limited to the discharge side of the system or anywhere from the discharge valve through the receiver/dryer and condensor and up to but not including the T/X valve.
It has to be remembered that this part of the system in most instances is running 120 - 300 psi depending on circumstances (normally around 140 - 200) so any leak there is usually real easy to find.
Low side leaks are more common and tend to take place when the pressures balance which is in fact when the system is not operating which again brings us back to potentially the T/X or that general area.
Alan S
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sdabel
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Post by sdabel » 23 Dec 2004, 10:23

Update on this:
The XM was in again yesterday and they couldn't find any leak at all. They were asking about behind the dash leaks also. I will do some more research on this and perhaps take out the glovebox for them and they will try again next year. I would prefer to let them take their time and do it properly than jump up and down and make them do a rush job the day before christmas.
Pity as we will now be driving to Melbourne in an Astra instead of flying first class in the XM. [xx(]
Seasons Greetings
sean
(from very hot Adelaide)
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Post by 406 V6 » 08 Jan 2005, 01:04

Have them to put a special UV leak detection dye. I believe Robinair makes one.
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