I have a high pitched squeal at idle. (1995 XJ6) It bothers my wife more than me however I have made efforts to eliminate it. My alternator wasn't charging at idle so I've replaced it, as well as the belts and idler pulley.( All needed attention so no loss) I still have the noise and am looking for advice. If you raise the idle just a little and it is gone.
You really cannot hear it in the cab but I'm sure it is leading to something.
Any suggestions?
Regards
fmfz12007

 

since you just replaced the alt belt, i would do the following..
1. Check for tightness of the alt belt
2. Grab a can of wd40 spray it at the alt belt see if the noise goes away,
3. Do the same for the other belts
4. Once you eliminate on which belt thats making the noise you can either replace or adjust it.

 

Have you checked to see if the alternator suppressor is plugged in? or may need to be replaced?

 

The crank dampers do become de-laminated sometimes.

bob gauff

 

do you still have your old alternator core/casing?

 

Thanks for the suggestions , I am pretty sure it is not the belts but will try the wd40 trick. I am not familiar with the alternator suppressor, where is it located? (I really should invest in a repair manual I suppose.) I take it you have had such a problem in the past?
Regards,
fmfz12007

 

Since I have seen several internet posts regarding belt squeal in Jags (poly vee belts), I will post my own story.
At first I thought it was occasional timing chain clatter, but as the noise slowly developed over the next 2000 Kilometers, it became clearer as a alternator belt squeal, for 10 or 15 seconds after start, (replacing the charge in the battery), or when the radiator fans would come on (especially when the aircon was on), or opening/closing windows, and this would be supported by the voltage gauge dropping while squeal and coming back up as the belt started to grip again.
I tightened the belts, it screamed like a banshee, I sprayed belt grip on (even though the can said don't apply to poly vee belts), it screamed like two banshee. I replaced both belts, it screamed like three banshee. I took the belts off and washed them in warm water with mechanics hand cleaner and a nail scrubbing brush, and they felt more grippy. I sprayed the pulleys with engine cleaner and cleaned the vees with a screw driver and paper towels, to get as much gunk out of the pulleys as I could. I finally sprayed the pulleys with contact cleaner to remove any residue, refitted the old belts, still a little bit of squeal, a little tighter almost no squeal, a little tighter, and finally the squeal has completely gone. The gunk in the bottom of the vees of the pulleys may have been stopping the belt from sitting down in the vees properly, causing it to slip on the crests of the vees, the gunk was also contributing to a lubricating film on the belts. I have read and herd, that unlike conventional vee belts, over tightening a poly vee, can also cause belt slip, due to the belt being designed to flex slightly, to bite on to the side of the vees as it contacts the pulleys, too tight and they will not be able to acheive this slight cupping action. This solved my problem, hope it might help some one else.

 

I had very similar symptoms you describe, convinced myself it was the water pump so I had it rebuilt. No fix.

It wasn't until I brought it to a local shop to check it out for a now-suspected power steering pump issue that I found out it was the harmonic balancer. Found a good replacement at a local junkyard, got incredibly lucky.