One potential way to get information on whether tensioners have been replaced is to put a magnifying glass on the valve cover bolts and look for evidence of removal. Many of these boltrs have some corrosion on them which would be disturbed, especially on the R models with the hood openings abouve the bolts.

 

When I performed the inspection a month or so ago I had researched to nth degree before I started. SO I ordered all parts up front, I didn't want to take apart and sit waiting for delivery. I started on LH side which was more difficult than RT. I 'd found they were already replaced like Doc. SO I'm thinking no need to do RT!! Well I had new plugs to install as well, when I pulled the plugs on the RT side I had oil in 2 wells, so since I has half way there and I had the seals I pulled the Valve cover and replaces all seals and gaskets.

Moral: To check use RT side of car first., Some have re-used orig gasket I'd prefer to replace with new when I took things apart and replaced the six seals/side) and now I have a new set of tensions in the parts crib but at 5k/yr it maybe many years before I use them!

 

Actually they were factory instead of replacements.
Here was my blow by blow thread at the time (June 2011)
https://www.jaguarforums.com/forum/x...nsioner-55895/

 

A few months ago I started hearing sounds from the tensioner area. I have a 2002. I finally decided to take the plunge and had the tensioners donenandnsure enough, I had the third gen metal tensioners. The right side showed signs of a problem. The plastic wear shoe was almost completely worn down. Now I have new tensioners bust it's something to be aware of in the future.

 

on my 99 xk8 conv it was pretty simple to get at the bolts for the valve covers was more a matter of getting the body to co-operate than removing the bolts lolol. the 2 bad ones are the lower back bolts on both sides. i used a couple of 3/8 extension between the block and heat shield as a pry to make room for a 1/4 socket, swivel and extensions. the smaller body of the 1/4 drive helps getting in there easier. if you need to really work to break the bolts free they've probably have been over tourqed. so replace the gaskets while your at it. both sides of mine were leaking . i found a kit with both gaskets and the large o rings and will back track for it if you need the info . i re-used the bolt o rings .