Thanks to Brutal for all his expertise! I was hoping that when my tensioners were changed out they would not be cracked. But oh no. My 1999 XK8 had 41K miles on it when Bill changed them out this last week. The truth is just do it now and do not wait. Thanks to this site and the great advise from all.

 

+1

 

I don't like scary stories

 

I thought I was safe with 31K miles on my engine but who knows???
Did you have any indications that the tesioners were less than perfect? Any rattle at start up?

Does anyone know if there is usually any indication of a problem before failure? Can I wait for a rattle at startup and then get them changed or do these have sudden and catastrophic failures?

Would you believe I have the same issue with my porsche boxster...rattling from the timing chain at startup from what is probably failing external chain tensioners!! A guy just cant get a break....

 

How about a Scary Picture of what can happen if the Cracked Tensioner Bodies completely split apart:

 

Looks like I have to order some parts and do a lot more reading. Any suggestions on where to buy the tools to lock the cam?

 

There are no indications for cracked. They can rattle when the pads come off. But then again youll need even more work like upper chains cause they streatch when they get chewed up after they come off. Time and miles, time and miles and time time time........

 

Had mine done this week - both cracked.

 

yeah I've bought them off ebay just need to have someone put them on.

 

Yeah, Werks II motorsport, Porsche tuners/racers told me that even Porsche has plastic tensioners, toyota does too, it's not that uncommon. I think there's just some other root cause in the Jag system that is a catalyst for this fatal flaw.

 

JAGUAR V8 1997-2010, 2 UPPER TIMING CHAIN TENSIONERS | eBay

 

Cheaper by a lot at an on-line Ford store.