I took the advice of so many on here and looked at my secondary chain tensioners in my 1999 XJ8 w/95,000 miles. Note that I had no symptoms of a problem (noise, rough running etc...).

I was rather shocked at the condition of the left side (bank B) sec. chain tensioner.

I had the "usual" split down the middle but the worst part was the "top" of the tensioner that the chain was riding on. The plastic had totally broken off and the chain was riding on the bare metal substrate! I found what was left if the plastic "covering" in the bottom of the head cavity.

I've included 2 links if you would like to see. The pics are a bit washed out but...

Side view of the crack (pretty much normal on these type of tensioners).

http://brianengel.net/JagPics/IMG_5891.jpg


"Top" view of whats left of this side of the tensioner. Note the grooves the chain wore into the metal.

http://brianengel.net/JagPics/IMG_5892.jpg


Of course I am replacing them both but I think I got as close to "death" as possible with this engine!

 

Please, don't lean on the rail!

 

wow, very suprised it never jumped off that thing! Would the chain also be damaged from that abrasive wear on the tensioner substructure?

 

I wonder that myself. There is nothing obvious, the chain looks good.

I am a bit concerned that the chain maybe streched too much.

 

wow...scary. Does anyone have an estimate of what a certified shop (not the dealership) would charge? thanks

 

i would like to know also , so i dont get ripped off

 

I actually found out today my timing chain snapped and so i called my mechanic and he said for parts and labor he was talkin $2,000. i am not sure how accurate that is but thats what i was quoted

 

There is a way to replace just the broken secondary chain and tensioner without removing the timing cover, but it is not a Jaguar factory approved procedure or parts source and I haven't done it.

What your guy is likely quoting you is for removing the timing cover, the primary chain, replacing the secondary chain and reassembly. That's the time when it is false economy not to replace both of the primary and secondary tensioners, primary tensioner blades and guide rails, associated gaskets and oil seals, and all four new timing chains unless the mileage is extremely low and there is no damage evident to the other chains. In that case, $2,000. is low.
Lots worse if you bent a pair of exhaust valves.