Thought I'd mention it here in case anyone has same problem. X300 use Denso 10PA compressor but the XJ40 can have the same issues.
I've been living with a noisy compressor for 3, maybe 4 years now, since its been working fine and I thought repair would either mean a replacement or at least compressor removal and then regas which would be a major PITA, I thought I'd just leave it until it fails completely. As it turned out the clutch bearing can be replaced with the compressor still connected to the system and I've only just found out a week ago
I've purchased a replacement bearing(30x52x22mm), which cost £12.56 and proceeded with repair which turned out to be very simple, rather very rare thing for a Jag
Had my brother hold the clutch and I've undid a bolt in the middle holding it, all done from underneath the car, then I tried for 25 minutes to get to the circlip holding the clutch only to give up. I've undone 4 bolts holding the compressor, moved it back by maybe 15cm and could finally see this devilish contraption and could get my circlip pliers onto it!
Circlip then removed easily and the whole clutch came off. I did make sure not to loose two tiny special washers while taking it off.
Bearing was hammered out and new one hammered back in(using the old one).
Fitted it all back
and the noise is finally gone!
Surprisingly the old bearing seemed fine, no damaged to rollers or seal, only movement was back and forth but only by maybe half a mm but that was enough to create all that annoying noise
Very happy with results!
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.