I recently had my primary and secondary tensioners replaced. As you can see they had started cracking and I had no indication of problems, the car was running fine.
I paid a local mechanic shop who, with an extensive search and a lot of questions, determined they were qualified to do it. $800.00 later. I didn't mind paying, am planning on keeping my jag for awhile.
I have a 99 XK8 with 54,000 miles on it, I bought it off the original owner who had no clue about this potential problem.
I have to thank all on this site for pointing out these issues when I asked some questions regarding common problems with these awesome cars.
Quite a few experienced and friendly jag owners here, great place to be...
I am posting a picture so you can see the old tensioners.

 

Nice one on getting the tensioners done bigguy.....looks like they were certainly on their way out and would have caused issues at some point in your future.

Glad we could offer advice and that you took heed, hopefully making your Jag trouble free in that dept for some time to come.
Appreciate you taking the time to post this up...................always good to help serve as a warning to others

 

I found the best deal for jags that don't have this issue is a 2002 XKR. They have the metal tensioners, so supposedly don't break. Newer cars have an upgraded engine - and are usually more expensive.

Sounds like you caught it before the dreaded engine failure these can cause!

 

I agree and would love to buy a newer XK8 or XKR with the 4.2L . As you mentioned the cost, eventually I will step up and make the investment, but I have other toys as well. This is my first jag and I always leave cars better than when I bought them, this one will be no exception.
The original owner bought this off one of local dealers at an int'l car show, which had been sent to Germany where Arden did some work to it such as lowering, wheels and tires, body kit.

J

 

As a rule of thumb while the tensioner job is being done also replace the water pump and thermostat, as a complete job......precaution is worth a fortune

 

I just did mine tensioners and guide on my 1998 XJ8 4.0 the guides had cracks and the tensioners had wear and were starting to crack .It had 96000 km not a bad job I took my time as I have never worked on one of these. I changed the water pump which the bear was very bad also hoses t stat and plugs .Thank for the info on the site.
Mike