So this has been going on for a while now and I've been trying to sort it to no avail. Hoping someone here might have some ideas. I have an 2010 XF Supercharged and there's a "chirping" noise from the supercharger when it's on boost. I've tried to get it in a video here, you can hear it if you listen carefully:

(less obvious in this one)

A bit of history: This started when my XF suffered from a known issue (I believe) where the small plastic coolant pipe above the supercharger broke - The first four years of it's life it spent in the Texas heat and cracked (the same happened to the intake Y pipe). This leaked coolant onto the belt and it started to slip, and make a rather loud squeaking noise.

I replaced the water pipe and then the supercharger belt, and the squeak definitely got quieter, but we're left with this "chirping" sound. I decided it sounded like pulley noise and thought it was quite likely that the coolant could have leaked onto the supercharger idler pulley (number 9 in the diagram below):



I've just replaced that pulley because it had a bit of play in it (maybe 1mm or so) and the noise is still there. However, the new pulley, torqued to the correct amount (and even slightly tighter) still has a small amount of lateral play in it.

I haven't changed the pulley above it or the one on the tensioner, because I couldn't feel any play in them, but I guess they could be next on the list.

I'm also slightly concerned the water leaking from the pipe has got into the supercharger somehow - though not sure if this is feasible or not.

I'd like to get this nailed quickly as I believe in California (where I live) the supercharger is covered by a Jaguar warranty up to 70,000 miles and I'm currently on 67,500.

I guess my questions are:

1) Should this brand new pulley (number 9 in the diagram above) still have a small amount of play in it (1mm or so) even when torqued correctly? Could this cause the chirping noise?
2) Is it worth replacing the two remaining pulleys (upper pulley and pulley on tensioner) on the supercharger belt ( even though I can't find any play in them?
3) Is it a fair assumption that becaue the squeak only happens when the engine is under load, it's a problem with a pulley somewhere on the supercharger belt rather than the accessory serpentine belt - I haven't even looked there yet.
4) Could water have got from the leaky water pipe into the supercharger, and would this cause a noise like this?
5) Jaguar had a TSB and instructions for installing a Spring Isolator in the supercharger - could this solve the noise and would it be covered by the 70,000 California emissions warranty?

Really appreciate anyone's opinions/ideas/suggestions on this

Thanks guys

 

OK, I've managed to replicate it whilst stationary by revving "sharply" - if you slowly increase the revs it doesn't happen - I'm assuming this is because the supercharger isn't under load unless you sharply rev.


It sounds loud from the back of the car so I guess it could be an exhaust leak, but that might just be the sound echoing in the underground carpark of my apartment complex.

I tried the "spraying water" trick on the belts (as best I could with the intake still attached) and it didn't do anything.

Help me, Obi wan, you're my only hope

 

Your pulley shouldn't have any play in it. I would think the bearing has gone bad.

 

That's what I thought, but I've replaced it with a brand new pulley and there's still play! I think more investigation is required.

 

the snout that the pulley attaches to has a rod and bearings inside that turn the screws.

 

There have been posts on chirping that sounds like a supercharger pulley but the issue is actually a ZF transmission squeal. It means the trans fluid is getting old and the way to address the issue is to do fluild/filter swap.

Here are a few other posts about it:
https://www.jaguarforums.com/forum/x...n-chirp-56905/
https://www.jaguarforums.com/forum/x...esolved-84204/

If you are sure it's coming from the pulley/belt area then read this thread:
https://www.jaguarforums.com/forum/x...rp-cold-65777/

Try spraying a soapy solution on each pulley until the noise goes away so you can narrow it down.

 

Or to be 100% sure. Just remove the blower belt and do a bit of driving. Quick and easy.

Does not hurt a thing and it totally removes the SC, belts and pulleys. The only for sure way to know.
.
.
.