Over the last week or so I have noticed a ticking sound when my 04 XJR is running. It sounded like a top end noise like a lifter when the oil is low or thin, but it is not related to engine rpm. I repeat, it is NOT related to engine rpm! It is loud enough that a passenger would say, "what it that ticking sound?"
If I an in park and gently increase the rpm, the noise does not change, but if I bring it up to 3000 rpm and take my foot off the throttle, it might stop for a few seconds, then start again. Its driving me a bit nuts...ideas?

 

You need the mechanic's stethoscope, i.e. a long shank screwdriver placed on a likely spot of noise then listen at the blunt (handle) end. YOu should soon find it.

FWIW, (and only my opinion !), it could be the variable valve timing device on one or other of the cylinder banks.

 

Two things:
1. I am pretty sure the XJR doesn't use variable valve timing.
2. It is not related to engine RPM.

 

I am running out of ideas, but the fuel vapour purge valve might be clicking away to purge the vapour canister. However this should stop when it's finished. Also try turning off the air con and see what happens. That is not revs dependent unless the compressor is whining. There are a couple of valves in the aircon assembly.

 

does it go away ever? it does sound like the evap purge valve

here's a thread:

https://www.jaguarforums.com/forum/x...icktick-90401/

 

Thanks guys! I read the link and believe that to be the noise...purge valve!

 

yes, i've got the same thing and thought it was a sticking lifter, I was not happy until i searched this out.

 

Once you realize it's not a motor issue, it becomes easier to ignore. We don't notice it anymore.

 

I found this how to video, very good; and xk8, but it should apply.


there is another video he did in the list to the right showing how to remove the fender liner.


*you can also see the foam 'sleeve' that jag put on the xk8, starting in 2006 I believe, to try to quiet the valve down.