1998 4.0L lwb xj8 im getting a tapping noise on first start up,ive changed the top tensioners about a thousand miles ago so im wondering what else it could be.
having searched the forum im thinking maybe vvt? does this car have vvt? or maybe belt/pulleys.
after a few minutes a quick dab of the throttle will usually clear it, so im thinking oil pressure,eg,vvt
it did this before the tensioners were changed so i dont think its them.
if it is vvt how do i remedy this myself ( cant afford professional spanner men!)

 

It sounds to me as if you have the right possibilities in mind. Yes, yours has a VVT. Oil specification change has been rerported to fix VVT noise. Check the archives for particulars.

 

just out of curiousity, where would the vvt be located? I understand the oil seal sometimes lets go, is it an easy fix?

 

Yep, -
The VVT s are located at the front of each intake cam, making them at the front of the valve covers. You might notice the solenoid connector protruding through the covers. XJrs have no VVTs and AJ27 engines (beginning MY '99) have a different arrangement for th ebush and solenoid.
If the tapping noise is indeed a vvt, you don't need to worry much about it imn my anything but humble opinion. If it is a sign of a bad or butchered tensioner- well you seem to know that story. Removing the VVT will take the exact same operations as changing the tensioners with regard to timing he cams. You will not be able to use the so called zip tie short method, though.

 

Here in Detroit I run 5w-30 in the winter. Once the minimum temps get above 0 Degrees C. I switch over to 15w-40 and that quiets them down nicely. Last summer it was really hot and dry here and I ran some 20W-50 that had been on the shelf in my garage for a while. Everything was silent but when it turned cold I ended up changing it a little early because I could hear that the starter was laboring.

Regarding the VVT seals, a Local European Car Mechanic said to replace the one on the VVT control valves. It's a hard plastic seal that wraps around the snout (Bush Carrier) of the control valve and seals to the ID of the VVT. Oil goes in and out of the VVT through this snout. I don't know if the front timing chain covers have to come off or if you can get it done by just opening the valve covers. The good news is you won't need to take off the VVTs and disrupt the cam timing to change this seal.

I can't say positively it will work because I've kept my car on a diet of thicker oil during warmer months and it solves the problem for now.