I am investigating a squealing belt noise on my 2007 XKR that happens mostly when the engine isn't started. Also I hear a rattling when the engine is under a heavy load at moderate rpm that sounds like engine knocking, but could also be a rattling pulley. I suspect a pulley on the supercharger belt.

Any tips on investigating this issue? Anybody done it before? I am going to remove the belt and check the pulleys and tensioners. This appears to have to be done from below. Hopefully it's just an idler pulley so I don't have to raise the engine...

 

I have this on my 07 xkr. It stops after a minute or so. Had it on my old 04 xk8. Never did anything about it. Never had a knocking noise though.

 

There is a TSB on this (sorry, i'm moble, so dont have it handy.) But they replaced the idler pully with an updated version.
Vince

 

Well there ya have it.... but I wonder how much that is gonna cost



Loth

 

Here is a prior thread on the subject..
https://www.jaguarforums.com/forum/x...eather-120168/

Of note is that that thread was started by the same OP with the same question....

BOL
Vince

 

It is true, I have asked about the source of this sound before. But now I am actually getting off my *** to try to do the work. I'm really just trying to find any tips or tricks on removing the belts to inspect the pulleys!

BTW the belt squeaking sound was not impacted at all by the belt dressing.

 

Update! I had only about 1 hour of daylight to work on the car, and all I managed to do was get the front lower engine splash shield off. Then I realized I was supposed to get the rear one off. Oops!

So I removed that one, too.

Man, this was tough because the car has apparently had this cover off a few times already and there were different and mismatched fasteners for all of the screws. I will go ahead and replace the front splash shield because it is somewhat mangled from what must've been a minor accident by one of the previous owners.

The worst part is, I still don't see how I'm going to access the bolts for the tensioner, and/or reach in there to maneuver the belt around. The shop manual does very little to show how little space there is to work with down there!

 

Looks like I need one of these doohickeys.


I should've bought that first!

Also, the TSB says this:

Supercharged (SC) vehicles: replace the FEAD belt and idler pulley with new flanged idler pulley and belt;
and / or replace supercharger idler pulley with new grooved idler pulley, tensioner, pulley bracket, and drive
belt.

Does this mean that once I find the offending part, I must replace all of those parts (on that belt) because a non-flanged belt will not work with a flanged pulley/tensioner (and vice versa)?

 

I assume you have a manual for the task, but if your winging it, this should help a tad...


BOL
Vince

 

Thanks for that. Any ideas if upgrading a pulley to a grooved one requires replacing the belt with a grooved one (and also the tensioner)?

It appears the tensioner pulley does not come apart from the tensioner itself so if I could avoid having to replace the tensioner that would be nice. I don't have a lift or a garage and I'd be a little but nervous raising the engine in my driveway!

 

Any ideas? I guess I'm just going to check the tensioners and pulleys and then put everything back together and take it to a shop, because with the amount of time I have to work on this, I will miss the whole fall convertible season!

 

Not having done this myself (shop did mine), and also the fact mine is a N/A motor, I lack your complexity.... However it does not look like rocket science.
The TSB leaves it to you to identify the squeaking pulley, but is assumes the idler pulley on the main serpentine (FEAD) belt for both NA and SC motors. I would start there....

No belt replacement is required to put a new pulley in place, but if it shows any signs of wear it would be as good a time as any. (A shop following the TSB will replace the belt as part of the service.

Your problem, is that you have two idlers. The supercharger is easy to reach, but to get to the FEAD pulley, you need to get the Supercharger belt out of the way first.

The TSB also hints that the tensioner pulley on the Supercharger may be known to squeak, hence the "option" to replace it as well.

If I found myself in your shoes. I would replace both idlers, and both belts, and call it good. I however have 80K on my car so my belts are sure to show some wear, if you have significantly less you could skip the belts, as today (unlike yesteryear) they are known to last a very very long time...
If the squeak persist, then you missed it, and the SC tensioner would be my next move.
I'm not a fan of getting that far in to a task and pinch pennies, just to revisit it later when belts are due.


BOL
Vince

Also note that the tensioner has a 3/8 slot (may be 1/2?) to insert a standard ratchet head into to release tension. no "dohicky" required.

 

Thanks, Vince. Unfortnately, I bought the doohicky already, but it can only help because I have little tolerance for maneuvering around in small spaces (lots of cursing and frustration) May come in handy later.

I think I will take your advice and replace both idler and belts. I just wanted to make sure a new belt and idler was going to be compatible with the existing tensioners.

 

Should not be a problem, but then we are not talking about the replacing the tensioner pulley, right? That is not identified in the TSB, except as an all-in option on the supercharger side of the house.
The only task involving the tensioners is to release the tension so you can let the belt go slack. The stationary idler can then be removed and replaced, and the belt slid back over the tensioners.

Just keep in mind that the part numbers for both idlers is different. I would hope the difference to be visible when in hand...

 

When I say replace the tensioner, I meant the tensioner and tensioner pulley. I don't believe the tensioner pulley is available separately (or is it)? Thanks for your help!

 

Ahhhh The light bulb flickers.....
So you are going to replace all 6 parts regardless of where the squeak is?

I didn't catch replacing the tensioner as part of the SC procedure.... Thought it was optional, sorry.

As the squeal is common to both motors, I bet the FEAD idler is the sole culprit, but they have obviously seen otherwise.


(I think I'm digging a deeper hole here.....sorry...)

 

So I guess the question is... why does the supercharger's new idler pulley design have a groove in it (which requires a new belt and new idler pulley and presumably new tensioner), whereas the idler pulley on the FEAD belt simply has a flange?

I have to believe that my idler pulley is actually bad (either one on the FEAD belt or supercharger belt) and even replacing it with a new one of the old design would fix the issue (along with new belts). Hopefully when I remove the belts, I will actually be able to spin the pulleys and it will be obvious what needs replacing.

I'll have to take another look, but I thought I already saw some grooved pulleys down there.

 

OK, so I just sat here with the manual and walked through the full meal deal for a SC motor.
In honesty, I would not try to replace the tensioner unless I figured it was indeed the culprit.
Working on a dolly around a floor jack (required to lift the engine off the motor mounts) is problematic. Not impossible, but it will inhibit your flexibility under the car as you will undoubtedly need a few contortion skills to deal with the nose of the motor.

Too your question (and I wish someone that has done this task would jump in here) I’m not sure of a correct answer so I’ll ramble mechanic gibberish hoping some of it helps make sense of the issue!
Both FEAD and SC belts are grooved. According to the manual the FEAD is a 6 grooved belt, while the SC is an 8 grooved belt. To carry the science forward, more grooves equals a larger contact patch between the belt and pulley.

Why this would be needed on an idler escapes me, as it is simply a routing pulley.


COmmon sense tells me you cannot make a major change in the design of one or two pulleys (groove width, depth, or sideways location on path) in a system without replacing them all, so whatever was done to the new pulley and tensioner has to be minimal or it would mess up everything else.

In the end, the idlers are pretty easy to do, the tensioners not so easy.

If you opt to do the SC tensioner, you’ll need new engine mount nuts (toss the old ones), and an o-ring (see service manual).

I’ve beat this horse enough, sorry I can’t offer more. Keep in mind the TSB holds Jag to 2 hours for the job, so if you hand it over, at least you know the parts prices and labor going in!

BOL
Vince

 

Well I finally had an hour to get in there.

I was able to get the supercharger belt off (partially, at least enough to check the pulleys), but I was not able to get the FEAD belt off. Definitely for the XKRs, access is very tight without removing coolant hoses, etc. You definitely need a purpose built tensioner tool to loosen the tensioners on the XKR. Even if you can manage to get a regular length socket wrench on there, there's very little chance you can actually provide enough torque to move the tensioner out of the way! Plus the way the hood opens, you can't exactly stand in front of the car so you end up doing everything from the sides and underneath.

FYI the supercharger and FEAD belts are already grooved. The supercharger tensioner doesn't appear to have grooves, which seems consistent with what I've been told. So there's no reason to replace the supercharger tensioner if it's not bad.

Now I just need somebody to yank on the tensioner loosening lever while I go underneath and remove the other belt so I can see what's wrong!

 

Update: After some thought and seeing how difficult access was in there (weighed with the cost of the dealer just doing it), I decided to just put it all back together.

Unfortunately I foolishly gouged the supercharger pulley slightly trying to get the belt back on with a screwdriver (hint, if it's not going back on, you probably haven't fully seated the belt on one of the other pulleys!!).

Anyhow, it's running like a top now. The screeching sound was threatening to show itself but didn't. I think I can live with it.

I did not put the engine cover (on top) back on, because the foam piece underneath was completely deteriorated. It seems to me that the rattling sound is gone. It must've been caused by the engine cover rattling on the engine!!