No aircon - kompressor kaput?

[Manbearpig]

Hi all. I have a 2007 Jaguar X350 4.2 XJR with non-functional AC. It has never worked in my ownership (1.5 years) and the car was laid up by the previous owner for at least 12 months before that. I think the previous owner hid the fault by selling in December!

Anyway, I tried re-gassing and found that the AC system was full and had kept up to pressure for over 2 years, so no leaks yay! However in doing so I also found that the system had been overfilled with a quantity suitable for the long wheelbase version of the X350. Mine is the short wheelbase version so someone somewhere in the past has read the engine bay capacity info sticker wrong. Assuming the system had locked-out due to over-pressure I hoped that refilling with fresh gas at the right quantity would fix it, and it sort ofdid so for a day or two, but then went back to no cooling (it may just have been a temporary placebo effect however!).

A Jaguar specialist then looked at it briefly and was of the opinion that the compressor was not reacting to signals from the AC control. I have tried to take it back to this guy but he is very hard to get hold of and rather evasive when I do - I think being in demand he can get more work done without hassling on with something so complex and time consuming..

I have resigned myself to doing the bulk of the work DIY. I have worked on simple systems in the past but this is several generations new and more sophisticated. Also the physical amount of other engine apparatus in the way is off-putting to say the least! At the moment I can’t even tell if it comes out the top or bottom!

According to online sources the original Denso compressor that is fitted to my car (JAGUAR part number 2W93-19D629-BE 2 Zone) has been changed for Denso part number DCP11010. Confusingly Denso's own online parts system lists this part substitution for the 3.6 and TDi versions and doesn't even mention the 4.2!

Another confusion - A Jaguar service bulletin XJ412-01 advised that the AC system should be flushed by a specialist if changing the compressor. This has to be done after disassembly and before installation of the new compressor which would of course preclude my DIY approach as the car will be undriveable.

I really need to keep the bills down on this job, if it starts going into the 000's it will be uneconomic for the value of the car. I was hoping to do the removal and assembly DIY and then just submit to a specialist for re-gassing at the end.

I would love to hear any advice about the compressor removal procedure, whether flushing is advised, and most of all if you think the actual diagnosis of the compressor being the root cause is correct.

[J44EAG]

AC is such a complex piece of kit and many of the tasks and actions required are likely to require specialist help and a high level of dedicated kit. Because of this and as you yourself have initially found out, any work on the system is likely to be beyond the abilities of even the best and most knowledgeable guys using this site. Most of us would put this type of issue out to an independent Jaguar repair facility on the basis of changing brake pads, oil or the odd wheel bearing is usually practicable for the vast majority of us, but air con is a specialist field which really does require a high level of practiced application together with the appropriate diagnostic kit and tooling.

You may get some advice from the guys here but at probably not the level you are hoping for.

I`d suggest you contact Matt Quail via the email address on the X350 header page in our magazine. You will almost certainly have to wait a while for Matts reply which may be due to his own work load, holidays etc.

Personally, I`d take this car to an independent operator and ask for a condition report and costings estimate.

Mike K

[PaulGover]

I'd second the recommendation for an independent specialist - an aircon specialist, that is, not a Jaguar specialist. In the old days, aircon was a rarity, and the Jaguar technicians were better trained than most; these days aircon is only slightly less common than muck, so any decent engineer who knows his stuff should be able to diagnose and fix problems. Also, I think it's actually illegal to tinker with aircon systems unless you're trained, as the chemicals used are very hostile to the environment.

I suspect my local Jaguar dealer subcontracts aircon work these days. (Sadly, having found a tame expert locally, he went out of business before I got him to fix my XJS aircon.)