My 2004 XJ6 (ex Singapore) slowly loses air pressure in the front when parked for several days. The prior owner replaced the front struts but it made no difference. Given the age, I am thinking it prudent to replace the compressor, so I began a google seach.

The first hit was https://aerosus.net/jaguar/xj-series.html, a German company that says all the right words about their products and backing, but I've never heard of them (not surprising, given I live on the other end of the planet). It's unclear who manufactures the compressor.
They offer:
Jaguar XJ X350 Air Suspension Compressor/Dryer €251 ($300) plus €81 shipping US $400 total
Jaguar XJ X350 Air Suspension Compressor with Bracket and Air Filter €335 ($400) plus €81 shipping to NZ - US$500 total
It also offers front comfort shocks for €359

Amazon lists compressor Part Number: P-2291 for $758 (€632) but can't be shipped to NZ and from AutoPartsWay parts $616 plus $379 shipping $995 (€830)
EBay lists https://www.ebay.com/itm/402083553309?epid=93715166 for $600 to which they add 15% Tax but can't ship to NZ
RockAuto wants $501 which totals $603 with shipping and 15% tax
So those got crossed off the list

Rebuild Master Tech in Florida wants $195 plus $80 shipping ($275) for a new RMT Brand. RMT is a family-owned business with some complaints online about their air shocks, but that is to be expected with a small firm.

Two questions:

• Has anyone had any experience with Aerosus or RMT's compressor?
• Aerosus also advertises a Residual Pressure Holding Valve Front. Can these cause a slow leak in the air system when parked for several days?

 

Have you checked the fronts for leaks and all the likely leaking places?

 

So far the R M T compressor in my 04, works great,.
Lifetime warranty, free shipping.& sales tax for less than $200.

 

Can you tell me what all the likely leaking places are, other than the shocks and the compressor?

 

Thanks, that answers my question.

 

HI
I went with Arnott on my 2004 with 135K miles after I got tired of replacing struts. Not selling, but you can have my old one if you want it - but for $200 and a warranty I'd go with RMT. I had 4 of their struts, and only 1 ever failed, and they replaced it.

 

The original supplier of the compressors was Wabco. UK supplier here: -

https://www.berkshirejagcomponents.c...AtMgEALw%5FwcB

 

Rear struts, all connections on valve block and ballast tank in the boot, all plastic pipe connections

are all possible leak sites. Check the new struts too.

 

21 April 2021. Order placed with RMT today. Shipping to New Zealand. Follow this thread to see how it went.

 

Hopefully you will have good luck too, i have been pleased with mine so far.

 

28 April package arrived. One week from USA. Impressive.

 

I took the car to Europa Motors to see if the TCM needed a software upgrade, but they recommended against it. Since I was there I asked them how long it would take to install the air spring compressor - about an hour. Rather than do it myself, I left the car and walked back to the ferry. Next morning it was ready collect, and they billed an hour of work... including inspecting the suspension to say all the movable bits looked new except for one upper arm boot that had perished (but the ball joint was solid). They found the bedspring squeak as well... turns out the left front shock absorber - the shock, not the airbag, was the culprit. The shock has a 2014 date on it, and I believe it was installed in 2017 and has gone about 8,000 km since then. They said it was nothing to worry about and only replace it if the noise bothered me.

The old compressor had a lot of surface corrosion on it, with no date. It was a WABCO brand made in Germany. So this may mean it is the original. Since it was not broken, I'll keep it on the shelf.

I paid, hopped in and within a few blocks there was a new vibration from the front - sounded like the new compressor. Then the Vehicle Too Low warning came on and the ride went from heavenly-cloud to camel-race rough. U-turn, back to Europa, and immediately the owner and his top man were on it. I took a walk in the glorious Indian Summer weather.

They reported that the new RMT compressor did not have the lock fitting that holds the air tube in, thus the tube popped out after a bit of a drive. They said they took the fitting (sorry, don't know the technical term) from the old compressor and it now should be fine. No charge. I drove it through the city and it seems fine, although I will need to take it on a longer run to make sure all is OK.

About the slight vibration noise. Is it that I am over-sensitive, or might the shop have tightened the rubber bushings too much?

When I get the time, I will write RMT to ask them if they think the new unit could have been shipped without the locking fitting. I'm not complaining since all ended well, but good companies like feedback to ensure quality control.

I left the car in town, and will go over tomorrow. If I am lucky, the compressor will have been the source of the leak and the car will still be standing tall. If not, I'll keep hunting.

 

Think you are talking about the brass sealing ring on the air line, i believe its called an olive.
It seems mine was set up to cut the old one, with the nut off, then you stick the air line in, and tighten it.
Nut and olive were already in place, they may have lost the new one taking the nut off the compressor.

 

They must be having a water cooler chat over at RMT about the NZ shipments. I'm expecting delivery of two fronts any day now too! Stupid things are probably flying out the door - what a cash cow. The sooner I can sell this balloon barge the better. New Zealand is too far away from reasonably priced parts to the point where I'm ready to go back to a Toyota Hilux and be done with it.