i have a rattle that i cannot figure out were its coming from. it hits right about 3 gets really loud right about 3.5 then drops off as you get closer to 4.

any one have any good ideas what i should look for?

 

Accessory belt tensioner bearing(?)

 

OK, i will check that.

Is that a common thing?

 

Jaguar redesigned the tensioner arm sometime around '00. Lots of reports of failures, some even have fallen off.

That was just a WAG by the way.

 

i know that they were plastic at one point, i have the updated metal tensioner components.

 

the problem wasn't accessory belt tensioners. It was timing belt tensioners. The uppers tended to give out which would destroy the engine. I would suggest that you have the tensioners checked before driving the car again. In fact might be a good idea to have them checked before even starting the car again.

 

chazaroo,

I have already replaced the primary and the secondary tensioners. I replaced the chains and guides as well. But i will pop off a cover later and take a look and see if any thing is amiss.