About a year ago, my 2005 XK8 began giving a little rattle for half a second upon first start of the day. I understand this is the VVTs rattling until they are charged with oil; the oil having drained from them overnight. From what I can tell, this is not necessarily a serious problem, so I have given it little thought. I installed an OEM Jaguar oil filter, but worked no better than what was there before. I'm wondering if I should expect the VVTs to eventually give me trouble as a result. Thoughts?

 

While there have been reports of VVT's being replaced I cannot remember any failures. The standard recommendation is to increase the oil viscosity or just add a bottle of 'Restore'.

 

Anyone have a recording of the VVT sounds? I suspect my 2000 is doing it but just want to confirm. I've had the car for less than a year and haven't had much chance to experiment with oil & filters.

 

It is described as a 'ticking' at start-up below 1500 rpm's. Goes away within 30 seconds.

 

Mine is a distinct rattle that hardly lasts a second. But it is awful sounding for that second. And it only makes it if the car has been sitting for several hours or overnight. I will try to remember to grab a recording if I can.

 

You are more describing a chain tensioner problem.

While you '05 obviously came with the latest metal tensioners they have been known to fail. Not in the previous manner of losing their shoes or splitting and losing oil pressure but by the ratchet operation failing. That keeps the tensioner extended even without oil pressure. Without that function it is waiting on oil pressure to build to tighten the chain just like the plastic versions.

Best make a guess as to which side is noisier and pull a valve cover for an inspection. If the shoe is not hard against the chain or can be moved it will need replacing. Such a condition exposes the engine to the same kind of cam timing jumps as the plastic ones.

 

Could that be a chain tensioner failure? There was mention of a type 3 failing to lock a few weeks ago.

 

Really had not considered the tensioner since my symptoms seem to match the descriptions I've read of VVT noise. I will def check that. Thanks!

 

I'm not sure what it would look like if it failed to lock in place, but I assume if it was a secondary you would be able to see slack in the chain and be able to push the shoe in. If it was a primary it would be almost impossible to observe.

It probably isn't a tensioner; that one reported was most likely a freak incidence. The VVT is the likely suspect.

 

Quick test: Throw in a can of RESTORE. If sound goes away it is VVT wear. Still hear it, tensioner.

 

Is Restore actually that good? Certainly worth a try. If it works i'll be very happy. Thanks!