Hello,
First of all, I want to thank the many forum fellows that have provided me with information on repairs for my VDPs and now the recent XJR that I am working on.

The next issue is that the car has a rather noticeable clacking, thawaking sound coming from the left side of the supercharger air intake units. It does this especially if idling and in drive with the brake pressed. Very little sound from the right side though. Is this something usual and if not, what may be the cause? I have found some supercharger rebuild kits on the web with some showing two bearings and some showing four, plus the coupler and what looks like needle bearings too. Would this fix the noise I am hearing or is the unit damaged and perhaps unrepairable? Which kit is the right one for this car? The two or four bearing one? Has anyone had experience replacing these bearing and parts and if so, what sort of an ordeal is it to go about the procedure? I am not opposed to doing the repair but I do not have a press if that is a necessary step. (Of course I can have that done at a local machine shop though I've always wanted a reason to own a press!) Attached is a picture showing area of noise. (Not my actual car)

It seems once you get started on a project like this car the problems and remedies are more than anticipated with the attendant expenditures adding up! Thanks a bunch guys!

 

The first thing you should do is remove the supercharger belt and start the engine. The engine will run and drive fine without it on. If the noise goes away, chances are it’s just the coupler and won’t require a press to replace it. The second thing is do you know if the secondary tensioners have been replaced? That could also make a clacking noise. How many miles on it?

On eBay.

This is the only supercharger coupler you’ll want to buy. DO NOT buy those cheap solid couplers as they sound like you have marbles rolling around inside the charger after you were chasing a noise to begin with and now it’s worse. Ask me how I and many other on here know. Don’t forget the oil and the red non-curing liquid gasket maker.

 

Well! What super helpful advice!!! The car is a 2003 with 156K and I do not know if the tensioners have been replaced or not. I will be removing the valve covers while I have the manifold off and will check on them, Good advice on the coupler too! I hope that is all it is. I'll let you know I hope today what I find while the belt is removed.

 

I removed the belt and the noise is still there. With a auto stethoscope and a little more checking, the sound is coming from the rear of the valve cover and also a bit of the same sound from the rear of the right side rear valve cover. Seems like a bad sign to me....will find out more when I get the valve covers off. Dang I hope this engine is not shot.....

 

At least you ruled out the charger.

What weight oil are you running in it? Do you know if the noise gets better or worse as it gets up to temp? Or is it the same no matter what temp it’s at?

 

There are several things that come to mind, however your closer inspection should make the reveal.
A broken or poorly adjusted rocker arm. I had a cracked rocker arm on an Oldsmobile V8 that would
cause a backfire at higher speeds. Or something simple, like a valve spring or dead lifter. You might
run some Seafoam in the crankcase to see if that helps.

 

Hello,
Yes thanks for the tip on removing the belt. It made no difference to the sound so on a positive note; it isn't the blower.

When the car is idling or even revving a bit it does not make the sound...or at least it's not terribly noticeable. When you put the car in drive while not moving the sound it very apparent. It sounds like it's mostly concentrated on the rear of the valve covers; especially the left,(driver's side).
The car needs a knock sensor on the left side of the engine and I plugged a used one into the connector and cleared the code which resolved the reoccuring DTC. It is not installed on the engine so it's not really reporting any knocking; if that is actually occurring. (It was making this clacking sound before I plugged in the knock sensor though I don't know what that means; if anything.) The sound is rather loud...sounds like valve noise but I can't understand why it only makes the noise with the car in drive. Does not seem to change as the car gets up to temp though. It makes the noise at higher RPMs though not sure if it's really louder or I just can't hear it over the usual engine noise.
It is not from the supercharger but since the blower assembly is bolted onto the valve cover, it seemed to be coming from there.
BTW, I just changed the oil and put in Castrol 10-40, which I use in my other cars. This car only had about 4qts when I changed the oil though...not a good sign. I have not driven the car except around the block since it arrived at the house. Needs too much work. The engine is just one problem; though perhaps the worst. Needs suspension repairs plus general fixes and cosmetic repairs; which I have been doing all along since I won't tear into the engine for a week or so. Plus it needs a good cleaning inside and out. I can't stand a dirty car...especially the interior.
Again, thanks a bunch guys!