98 XJR main drive / serpentine belt

[Zippyworld]

Help !

Opened a can of worms here, asked the guys servicing my car to change the supercharger belt as it was squealing
He said he would do them both so I said fine.

Now when the engine starts from cold the automatic tensioner pulley moves from side to side and causes a loud knocking sound. He is scratching his head now.

The car had no issue with this before it went in.

All the pulleys and tensioners are upgraded so any idea as to what is going on ?
Is there a specific procedure for the serpentine belt ?

After 15 to 20 seconds it stops knocking......

[Zippyworld]

Auxilary belt

[Zippyworld]

If my information is correct there is an automatic tensioner pulley for the auxiliary belt which is central (ish) and another tensioner for the supercharger belt. It is the former pulley that moves about, all seems well with the supercharger belt. Sorry if it eas a bit vague

[Zippyworld]

New pulley tensioner fitted now its fixed.
Really strange that one, the old one has been on for 16k miles

[Zippyworld]

Aaaaaaarrrrgggggghhhh.....
Its doing it again, it has only been used once !

Its driving me insane this, I am wondering if its something to do with the upper pulley upgrade the car had a while ago.
I would really appreciate some help with this, if its a new belt, and the automatic tensioner pulley us new what more could this possibly be ?

If it had the upper pulley mod would it not tequire a shorter belt oris there an adjustment that the mechanic has not made ?

Thanks

[Zippyworld]

I miss Jaguar Steve, he would have given some sound advice !

[Zippyworld]

Hi

Its the auxilliary belt thats causing the issue.
Supercharger pulley snd belt is new and uograded too.

It only does this from cold.

[Zippyworld]

melhookv12 said:

The TSB related to the A/C compressor misaligned. I believe there was a dowl missing.

Does the compressor look aligned ok.

Excuse my lack of knowledge, this is interesting, a missing dowel where exactly ?

Thankyou