Hi all,
Got a 1997 4.0 xk8 with the cold start vvt ticking/tapping noise, blip the throttle and it goes.
Just wondered if it was possible to disconect the solenoids untill i can afford to get this problem sorted and still drive the car?
Its probably only one vvt solenoid thats making the noise but do i just disconnect one or both?
Thanks for any help

 

Because of your reference to cold engine idle I assume that the issue you are describing has to do with oil pressure.

The VVT's simply operate off of oil pressure.

What weight oil in the car? How long since the last oil change?

If they quit ticking with a throttle bump, driving it should pose no problem.

 

what oil weight is recommended to solve this ticking tapping noise. i get a slight rattle for a very split second at cold start.

i have 5w30 castrol syntec sythetic oil, the synthetic seemed to improve it over the 5w30 dino oil ?

 

It had a full engine flush, 5w/30 semi synthetic oil, new Jag oil filter and the 4th gen top tensioners fitted only 100 miles ago
Sometimes it starts without the noise then 30-90 seconds later the noise starts just like a tappet noise, blip the throttle and it goes until the engine is cold again.
My question is if i unplugged the solenoids would the noise still remain from the mechanical side of the vvt or would it be dis-engaged?

 

Daywalker,
Is it possible that this problem started with your last oil filter change? I have seen problems like this related to a defective oil filter(anti drain back valve). Replace the filter to see if it helps. If no help you can always use the extra filter later.
Hope this helps.

 

No the noise was there before the filter change!
I have unplugged the vvt soledoids and........NOTHING!
same noise until throttle is blipped
So it looks like oil drain back from the vvt and when pressure is restored noise is gone
Thanks all

 

Are you sure we are chasing the right problem? The cam chain tensioners also cause a 'rattle' at low speed/first start up.

Have yours been changed? If not, they are an absolute must preventative repair. The penalty for a broken chain or jumped tooth is installing a new engine.

 

Are the top ones the secondary ones?

 

Yes uppers are the secondary, and i would pull both cam covers and inspect asap. If theyre plastic bodied, these are early style and very prone to breaking. Even if they look fine change to the later style metal bodied. When you pull the old ones youll likely see a crack or split down the side that lets oil pressure bleed off from the tensioner which starts all these problems. Dont put it off, as stated its cheap compare to an engine replacement.

 

Yep i changed to the latest 4th gen steel bodied top tensioners only 100 miles ago! to stop the noise but it wasnt the tensioners and the noise is still there on cold start as soon as the noise appears blip the throttle and its gone.

 

I have a ticking in my 99 XK8. It is synchronized with the valve cams. And it disappears at revving. The engine has 20K miles, its a rebuild. We changed all the tappets, but the ticking persists. A Jaguar specialist independent suggested the VVT as a source, and you are confirming it, he also mentioned assuring the oil flow. Everyone cautions about the chain tensioners. Changing the VVT is expensive, but if it works I'd do it. How can I get some assurance that the VVT is the problem, how do we do the diagnosis

 

Worn, ticking VVTs are usually treated with a can of RESTORE or similar product or a step up in oil weight rather than replacement.

 

What do you mean by going up in oil weight???

 

hi,
another long shot to potentially decrease oil pressure would be to remove the sump and clean the oil pick up screen.
they collect broken bits of tensioners and it can/could block oil flow. worth considering it.

good luck
steveeasy

 

Niels, you should post up an intro in the new members section New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum

Going up a weight means using a heavier (thicker) grade of oil.

 

There's lot's of info on utube about this issue.