Help!
I need any advice or experience you have with X300 Air con trouble.
My 3.2 X300's aircon was not blowing very cold, so I took it to an aircon guy who diagnosed a blocked TX valve under the dash, and referred me back to my Jag mechanic to see about having the dash removed.

There seems to be conflicting info on the internet, and my mechanic isn't sure either, whether the X300 has a separate TX valve or it is integrated with the evaporator. He thinks he won't know til he has it apart, and that sounds like at least an 8 hour job... (he told me doing this on the old series 2 & 3 XJ saloons was a 30 hour job !!).
A valve is about 110 NZD, but the whole evaporator is about $2000 NZD.

Someone else on the net has suggested defunctioning the valve by removing it's jammed contents, which would make the low-pressure side of the AC in the cabin run at a higher pressure. I don't know if this is smart or not, but I will ask the AC guy tomorrow.

Anyone had experience of this?

cheers, AL NZ

 

Hi AL NZ
I actually have this same issue with my A/C system in my XJR. When I was doing the research into tearing apart my dash to get to valve I think it was a replaceable part separate from the evaporator itself but the hard part was actually finding the expansion valve . I remember reading through a thread somewhere, where the OP replaced his valve and was able to flush out the evaporator but it took him 3 or 4 times to find the correct expansion valve.

I think best thing to do would be to actually pull the evaporator and valve from the car to see exactly which valve you have.

 

The part from Jaguar is a complete heat exchanger assy (evap core). The EXP valve is not sold/serviced separately (NSS).

The part is available from 'after-market' sources and I have purchased one to keep in stock if I ever need one. I think I bought it from 'ROCK AUTO' for about $20 with shipping.

Look for Part # GPD 3411483 or something like that.

DO NOT BUY THE ALUMINUM BLOCK-TYPE VALVE. The XJ40 used that style but the X300 uses the older style valve with the copper tubes attached.

There was a discussion on this topic in a previous thread a few months ago.

bob gauff

 

What's clogging your valve? Did the compressor eat itself? There's a thread or two here about desiccant bags in the rec/drier coming apart and clogging it with beads. Otherwise, unless you left your system open and a mud-dauber nested in there, there's not a lot to clog it.


However, it is not uncommon for an a/c man, faced with a problem he can't solve, to declare a TXV change is called for. Changing the TXV requires a vacuum & recharge, which fixes a lion's share of "problem not found" a/c problems, thus making said a/c guy appear to be a genius. Particularly if he was trained at a dealership; Can't file a warranty claim for just "evacuate and recharge" but you can for a txv change.... and as noted... that "fixed" it.


Back to your issue, if desiccant beads, you may be able to blow them out by back-pressuring it with compressed air. I believe there's a post in here somewhere.

 

About a year or two ago there was a discussion about the desiccant 'beads' lodged in the system.
I have dealt with this fault a few times with the XJ40/X300 systems and had to 'backflush' the system to get the tube and expansion valve cleared of debris.

The XJ40 is EASY as the valve block is accessed from the engine compartment.

The X300 requires the removal of the climate control unit assy on the bulkhead from the interior.

bob gauff

 

thanks guys.
My thoughts were along the lines of aholbro's - that nothing can get in to block it.
I presume this valve is a static part that causes backpressure, so the liquid refrigerant will expand to a gas as it passes through, thus losing temperature (Boyles Law, I think). Does it have any moving parts?
the idea of back flushing it with compressed air is appealing - I am not convinced a whole new evaporator and valve (price quoted $2000 NZD !!) plus many hours of labour is the first answer, although it may come to that.

It is a bit of a grudge spend! Usually I don't mind maintaining my car properly.
It is summer here, 30'C , and I come out from work to a Jaguar oven, so air con is almost essential..

will et you all know final outcome.

 

The expansion valve DOES have moving parts. The orifice is adjusted (minutely) with a balance pipe and thermal bulb. Other systems use an 'ORIFICE TUBE' that IS FIXED with no moving parts.

There are A/C system FLUSH products that are approved for cleaning systems.

This is available here in the U.S.
http://www.omega-usa.com/client/imag...yer-081213.pdf

There are similar products that will work.

bob gauff

 

Bad news from Bob in Post #5, above. ;-(
I only vaguely remembered those posts and had hoped one could backflush without having to actually gain access to the TXV. .....it's almost enough to make me go cut into my liquid-line and install an in-line filter, along with a new Rec/Dri "just in case.."

 

Sorry Al it's a dash out job mine was stuffed in 2010 was a $2500au repair cost hurt for a month then it was 33 degree's and 90% humidity forgot all about the cost

My A/C guy replaced all the foams on the doors at the same time

I pulled her out of the garrage last Monday the air con worked instantly better than my new X350 had my A/C guy check it as I and the wife are delivering it to Tasmania gas was still full
It's been on for the whole trip Qld was high 30's 90% humidity when we left am just sitting in a bar in St Kilda it's 36 degrees here in Melbourne dam that AC works well
Going to get my X350 checked when I get back next week want it to work like the XJR6

 

yes, Doc, I am resigned to the inevitability of it all... booked in for soon. Jag man busy this week.

so the mighty X300 R is off to a new home?
I am teetering on the brink of buying this one..

Jaguar XJR supercharged 1997 | Trade Me

I don't need it, my wife may object, I know there will be some heartache, but it's only money and I think it is one of life's necessary experiences - at least for a while..

 

I had the dryer canister (tube right at top of condenser in front of radiator) leak the pellets all through the system. What I did was discharge the system and disconnect all fittings. Then I proceeded to use high pressure air to blow out all the components. And pellets came out from every where. I then replaced the dryer canister and had the system recharged. It worked fine after that for about ten years. Then the compressor failed and had to be replaced. A few more pellets were found and removed. I also replaced the dryer and opened up the one I removed. When I found out how it was made inside I knew It could be installed backwards. If installed backwards it would be prone to open up inside and blow all that s..t through out the system. With the new compressor and canister it works great. Probably next summer i will have it serviced and replace the canister again and since I know how to install it I will be sure the installation is correct.

She worked great all last summer.