i have a 2001 jaguar stype 4.0, i am getting a chirping and squealing sound from my belt, that because i have changed the belt twice and it goes away for 2 days and then it comes back, nothing sounds like it is grinding so i dont think its a pulley and i just replaced the belt tensioner thinking it would solve it and it is still chirping and squealing, im getting really tired of this noise and thinking about getting another vehicle instead but really dont want to let my jag go, so please help any info would be great.

 

Try this - Shut the air conditioning system OFF - completely off, no air, no fan, etc. Make sure it is off when you start the car, then observe, see if the chirp goes away. If so, its the air con clutch.

The bearings on the idler and tension pulleys on this engine (all variations - s, xj, xk) are seriously underpacked with grease at the factory. They are usually replaced, but I first try repacking them. The metal bearing seal is easily removed from one side (with the pulley removed from the engine), then I clean and repack the bearing with a high temp disc wheel bearing grease. This works almost all the time unless the bearing is destroyed.

Thirdly - if the air con test doesn't work and the pulleys are either replaced or repacked, and the cirp persists, its the alternator bearing

All experiences I've had with the chirp.

 

well i tried the a/c and it still made the chirp with it on and with out it on, so i will try the alternator pulley next and see how that goes, but how can the alternator pulley make the belt chirp wouldnt that be like a grinding metal sound not to sure tho?????????

 

Sorry, my mistake - If the Air con is not it, and the idler and tension pulleys are either replaced or bearings repacked, then it is the alternator bearing, not the pulley - entire alternator must be replaced.

At one time or another, I've seen each of these problems cause a chirp or a clicking, so I usually work up from least expensive fix to most expensive.

 

I think at this point, if the belt is the correct one, and is fully adjusted, and the repackable bearings have been repacked.....

Then I would be tempted to give it a shot of Fan Belt anti slip, or WD40 and keep my fingers crossed.

If you remove the belt from the alternator and spin it by hand and you then hear a 'roller -skatey' type sound (bad adjective, sorry) then suspect the alt bearing.

I remember reading a long thread a while ago, where someone had changed the idlers, pulleys etc and they were having an odd belt issue, which IIRC was down to a slightly poorly positionned idler, causing all sorts of sound effects, from resonant vibrations to the stuck pig screech.

 

so what do you think i should do next?

 

As Richard advises, I'd take the belt completely off, rotate all pulleys and listen for anything that might suggest a bad bearing - water pump, alternator, ps pump, idler pulley, tensioner pulley.

You didn't say whether or not you pepacked or replaced the idler, tensioner pulleys. These are the most common culprits, but if they spin freely asnd silently without the belt in place, then you probably have a bad bearing in one of the "more expensive" devices riding on the belt.

BTW - the belt itself cannot be adjusted for tension. This serpentine belt has the proper amount of tension applied, and constantly throughout its wear life via the tensioner pulley which is spring loaded.