Rattle sound from XK8 during decleration
 

I have an XK8 and I get a rattle noise when slowing down, or when at idle and revved up on the way back down the rev range there is a rattle noise.


This is a video of a car doing the exact same thing. I just changed out the tensioners for new ones and the primary guides look good.

hi,
If your engine sounds the same as the video clip I can only think it is a slapping timing chain.

it could be a failed primary tensioner, or perhaps a problem with the tensioners you have changed.

id not run it again until id removed the covers and check the secondary tensioners indeed are primed, check for slack in the chains. then id take the front cover of and check the primary chains, from the sound I can only imagine a primary chain flapping about.

you could check oil pressure. if it was restricted it could stop the tensioners working properly. remove sump and check the oil pick up for blockage. pieces of plastic get inside the oil pick up. you will need to undo the oil pick up and tip it up to remove the bits.

hope this helps, lets hope it is something more simple.

stephen

did you use the shorter bolts on the new tensioners?

Thanks for the replies, so far.
 

Yes, I used the shorter bolts that cam with the tensioners and I torqued them down to 10.3 newton meters, manual says 9-11 newton meters. I will check into the oil pick up.

hi,
the oil pick up is a long shot, but worth a go. its a very short job. id remove your cam covers and check the chains are tensioned. did it make the noise prior to doing the tensioners ?.

stephen

Yes, That is why I did the chain tensioners. I didn't do the primaries only the secondaries. I will have to look into doing that oil pick up job.

Anymore Ideas
 

Does anyone have anymore ideas on what could be causing this noise that I can check into?