My Citroen XM 3.0 PR-Vestige

[Eddie nuff]

Dont forget mine is now officially a tart car, you know the one, sits in the garage all year, gets wheeled out to the show and then put back in the garage for the next 11 months

I would be tempted to take your car to a couple of meets where they lower em, spray em, put a ICE system in them that's worth more than the car and then screw the nuts out of em. You'll need to put your baseball cap on backwords, like, innit, like to fit in, but once you drop the suspension I can't see you being an outsider.

[Dean]

Car, check. Baseball caps from my yoof, check. Street talk, probably not street enough these days

I've turned my attentions to the A/C this morning, been charging it with 20psi and it keeps loosing it within a few days, not good! Maybe it wasn't just the condenser at fault, the long and short of it is I forgot to do up the condenser connections, hand tight with the old seals on it isn't really going to cut the mustard.
All new seals fitted to everything and pumped up to 15psi, will see if it can hold some pressure now. Fingers crossed.

Did I read that someone charged their own system? and I've been doing some research, seems like R34 is a bit hit and miss, R12 is still available to buy in America although posting would be troublesome read impossible, would like to gas with R12 and the matching oil since I went to the trouble of getting a new R12 spec condenser.

Any thoughts on this?

D

[White Exec]

XM AC is very efficient even with the R12 replacement, R134a. Manual states 725g for a refill, with a capacity of 135cc of SP10 refrigerant oil.

Do get the refill done by a professional, with the correct evacuation and gas+oil refilling kit. DIY is really not to be recommended, as it is impossible to (a) evacuate the system, and (b) get the refill quantities correct.

A professional AC regas here is about €45. R12 best avoided these days, for environmental reasons. Citroen recommendation is R134a.

[Dean]

No your right and I can't be bothered, nor can I justify buying the kit but I don't want to give the car to a monkey with a machine, I want to look at it and see what's what so I can talk with some sort of confidence about what I want.
Its common knowledge that R134 is not as efficient as the R12 which is why it was never used until recently. I saw this when my car was (converted) to R134, not as cold at all, also there is the problem that 134 seams to be a more leaky gas and causes blockages in the pumps looking at discussions on ac engineer forums.
Of course they never converted the system, the fill points are still R12 drier, condenser and all but two of the seals.
My system is empty of oil and gas, it all leaked out through the whacking great hole in the condenser about 6 months after the ( conversion).


D

[Dean]

Taken from a US Merv forum, written by an A/C engineer of some note.

R12 vs R134a
If you are toying with the idea of switching from the Factory R12, please do NOT and read on for the following reasons.

Efficiency:
There is no question that R12 performs better than R134a, but by how much? According to statistics, for an R134a system to have comparable performance to R12, the condenser must be increased by 30%. That is a huge feat. I am not whether that correlates which stating that it performs 30% worse when in the same systems, but one can make a pretty good judgement that if it requires 30% greater surface area to meet prior performance, it is safe to say R12 or CFC-12 is far superior.

Overall, HFC-134a requires a larger condenser capacity and increased airflow to keep system pressures within safe regions.

Longevity
Getting right to the point, HFC-134a does not provide the same level of lubrication circulation that CFC-12 does. For our particular models, this is the reason why generally more cars which have been switched over to R134a have more compressor failures than R12. If you keep your R134a system in perfect order, it should last as long, but there is no doubt its more difficult, and more prone to damage.
If you are compelled to stay with R134a, you must understand that proper lubrication/oil is critical for compressor longevity.

Lubrication
Remember you cannot and should not mix oils. PAG (Polyalkylene Glycol) oils use a variety of different additives and this is the reason that one brand should not be mixed with another.
Remember PAG Lubricate is hygroscopic like brake fluid -- it absorbs water, so a container must not be reused after it has been opened, or, ensure that the container is fully airtight.

CFC-12 uses mineral based lubricants.

Use of too much, too little, or the wrong viscosity oils can lead to a shortened compressor life.

In both R12 and particularly for R134a systems, a refrigerant leak, or a low refrig level decreases oil circulation, so try not to operate the A/C system if this is your scenario.

Service Ports
If your service ports do not have the red/blue caps on them, Get them!! They are the only defense against lost refrigerant if the valve stem opens at all. Once tight, they are airtight.

System Flushes + Compressor Failures
In the event of a compressor failure, flushing is not an adequate way to ensure that there is no debris left in the system. The use of inline-filters is the only way to ensure that long term damage to the new compressor does not occur.

D

[xantia_v6]

R134 is not as bad as it has been painted. For a temperate climate like the UK, the system should have plenty of capacity, unlike Nevada or Alicante.

The regulations in the USA are different to Europe, I don't think there is any use of R12 here, but there are R12 compatible refrigerants available ((which are illegal in the USA).

You need to find someone with the gear and experience to do the conversion.

[Dean]

It may have to be a mainland trip to find someone good I'm afraid, the guy I was going to have do it moved to brum.
I reed they need the system to be held under VAC for many hours once they have been opened up which could be tricky.

D

[White Exec]

Interesting.
The Citroen recommendation to use R134a goes back at least to 2001, the date of the TSB I have, so not a 'recent' specification.
I would be choosing a real expert, rather than a monkey, as you say.
The correct oil, and the correct amount of it, is crucial, as is the right amount of refrigerant.
Not sure whether the 2.0 system is less powerful than the 2.5, but our 2.5 AC is capable of freezing your nuts off, even when the outside temp is 40C - and with R134a.
I think I read that the original XM climate system was designed to achieve the chosen cabin temperature at any outside temp between -50 and +50C, but maybe, in 1989, that was with R12.

[White Exec]

Needs holding under vacuum for 15 or so minutes is my experience.
Can't vouch for Nevada, but Alicante is certainly not a problem, nor Ronda at 44C several years ago.

[Dean]

The 2.5 system was designed for the less efficient 134 so bigger condenser, the R12 system does not cool as well on 134 as by the looks of things was designed to run on a much more efficient refridgerant, I'm looking at getting an R12a fill mainly because its as close to R12 as you can get but it halves the loading on the compressor, 7nm required compared to 14nm for R134a. Will have to phone round next week and see what the experts say.

D