My X300 is an early 1997 version, no startup rattle but I was wondering is the upper chain tensioner something that should be replaced regardless as mine is approaching 100,000 miles?
I don’t have any history for the car before 76,000 miles so how do I know if this already has the new style tensioner, do they look different or did Jaguar already fit them to the 1996/97 models?

 

From Jaguar TSBs (the one's nobody reads)

 

The revised tensioner is a one piece heavy casting on the outside exposed portion with the raised arrow in the casting .

The original design has a valve clamp bar bar from one mounting bolt to the center

 

An old adage comes to mind.... something about "if it aint broke......"

 

Luckily after having a look it’s clearly the revised one, being an early 1997 it may well have been fitted from new.

 

i have a 97 and it rattles for like 2 seconds

do i care? not really