Open question to any Jag techs out there--

I have an 01 XKR with 17K miles. I have read that the chain tensioners have a tendency to disintergrate without much notice. One article I read said that a warning sign is after a cold start you hear a rattle for a second or two. I discussed with the Jag service manager and he concurred that the replacement is a good idea, but could not offer any help in when I should do it. He was just getting ready to do it on his XJ but he also had 79K on the odometer.

I have experienced the rattle, probably every dozen or so starts. If the chain tensioner breaks and the timing chain skips 2 teeth--I am told the engine is toast at that point. One tooth will make it run rough but the second tooth will drive the pistons into the valves.

Has anyone had this replacement done?? Seems like this is a latent defect that Jaguar should fess up to and do a recall.

any thoughts??

Gary

 

it's good insurance and it pay's well..lol

 

See below a few other members experiences and opinions that you may find helpful


having just suffered the routine wearing out of the secondry chain
tensioner,(lucky enough I was to catch it before it
disintegrated),how do the primary chain tensioners and chain guide
last in comparison to these,engine has covered roughly
116000miles.i no it would be good practice to renew the chains and guides as a matter of course,but cannot due to health at the
moment,just wanted re assurance in my mind from you guys,cheers dean
----------------------------------
Never heard of a case of broken engine due to a primary
tensionner failure. Never heard even of a broken primary
tensionner.
Secondary chain must not be changed, except if the plastic
ski of the secondary tensionner was already gone and there
was thus a potential abrasion of the chain. In this case,
the chain must be changed and the oil and filter renewed
(due to metal particles in the oil).
-----------------------------------------
I would just add my 2 cents that you insist that the 3rd type of tensioner is used as the replacement if u decide to have them done (Metal not plastic). also what about guides? when my chain snapped and I had everything replaced ($3k us) all the guides were cracked too! they did not have to pull the engine to do this.
-------------------------------------
Here are the entire nine pages of the 'V8 Timing chains and Tensioners'article they carried in the December 2003 and January 2004 issuesof the magazine. This applies to the V8 AJ26 engine in its various forms.
v8timingchainsandtensioners
The pages are deliberately scanned a little larger than normal
(1000 px wide) so you can see the detail easily.
This is not a job for a beginner! It is quite involved and requires
a reasonable level of expertise as well as the parts and tools
to do it.
For those interested, I quote from the article on why you may need
to do this job:
"The weak link is the upper chain tensioner, which is a double ended device with a fixed slipper at one end to guide the drive side of the chain and a spring loaded slipper the other side to
progressively take up slack as the chain wears.
Unfortunately, the plastic used seems to break down over time,
cracking and eventually disintegrating. Eventually, one of the
slippers will drop off, leaving only the metal frame to support the
chain.
The immediate result is a rattling noise from the front of the
engine; more worrying is the chance that the if the chain was
partially worn before the tensioner failed, there may be enough
slack for it to jump a tooth or two on the exhaust cam. One tooth
skipped and the engine will run roughly, two teeth and it will
self-destruct, with valves and pistons coming together.."


Jim

 

Just had my Jaguar XJ8 sorted with new chains, tensioners (both primary and secondary) new gaskets all round, oil and filter by Autospray in Cheltenham all in price of 1265. I cannot praise these people enough, the customer service is 2nd to none, what with regular updates including progressive photographs taken at every stage, free loan car for the duration and one of cleanest workshops I have ever seen! I'm sure they build things for NASA in their spare time!! if you need this work done, vist www.autospray4u.com. A+ ask for John!