I'm thinking of replacing my XJ6L (97 X300) with my friends XJR100, the issue is this....it's got 45k on it, it's last three of the vin is "500" which makes it the last one (I think) the thing is the original supercharger went when he put the larger pulley on it and he replaced it with a used unit with 70k on it and it's "grumbling" (loudly at idle). Is this worth fixing?, easy as a bearing, coupler, snout kit? Removal/replacement process difficult? My mechanical background is extensive and I'm not afraid of most tasks. I Just don't want to have to spend much more then the purchase price, bearing kits seem relatively inexpensive but the difficulty factor could play in. Plus the Mrs is already unamused.

 

Don't think the 500 in the vin has anything to do with it being the last made.
Just a coincidence. There is one on Ebay now last three digits are 906.
The last five digits are a consecutive unit # and weren't produced in any special order.
As for the supercharger, timing of the rotors "if" front bearings in the case need to be done would be the biggest problem. But these rarely fail. The seller of this kit may offer it as a service. This is kit without front case bearings.
http://www.ebay.com/itm/fits-Jaguar-...xUlLyS&vxp=mtr
It's worth fixing.
One more note.. It's easier to ask for forgiveness than to ask permission...

 

Another thing, Take S/C belt off and start it to confirm it is the S/C.
You can also see if it may just be coupler noise.

 

Oh, it's the SC all right, my stethoscope confirms that.

 

I would still recommend removing the supercharger belt so you can hear the engine idle without the noise from the supercharger before you buy it.
Rebuilding the front snout or changing the rear bearings (if you have the model where the bearings press out the back) is easy. Removing the supercharger is the harder part.


Unless your friend has had the upper tensioners replaced with 3rd generation units that should be your 1st repair before anything else