I am looking for any help and thoughts on the cold weather belt chirp.
Seems many cars, Jags included but they are more than just a car, have a tendency to have an annoying "chirp" from the serpentine belt when cold.

I know that the XJR has a double sided ribbed belt for the supercharger, but my chirp is not from the SC belt. I can remove it and the chirp remains.

The belts are not so old, 10k or so, and the chirp is only present for 2-4 min when cold (30-40F), at idle.

While trying to research this to find the root cause, there are many theories but no real cure, new belt, check pulley alignment, clean, belt conditioner etc.

My investigation shows that the noise is from the tensioner pulley, and that the chirp happens when the part of the belt that has been around the alternator . In this case, the belt is going from a tight flex inwards to the grooves to a reverse flex with the flat back of the belt against the smooth flat tensioner pulley.

My theory is that the belt slips when flexing on the tensioner and causes the chirp. When the tensioner pulley is new, it is coated, but this wears off. A new pulley stops the noise until it wears off. I propose that if the pulley were coated or the belt allowed to slip on the reverse flex, the noise would stop. Once the belt warms up, and flexes easier, the chirp stops.
I think the evidence that Jag introduced a double sided SC belt is some evidence that the flat side is a cause of noise.

As a test of this, I tried some soap water spray ONLY on that pulley and the noise IMMEDIATELY stopped.

I am wondering what the collective thought would be to a coating on the pulley or some lubricant on the flat side of the belt? This would NOT affect the belt pulling any of the accessory drives.
Was there a mod for the accessory belt to be double sided ribbed too?

I am currently testing with some powdered graphite lubricant sprayed on the flat side of the belt. So fay the last few days it has been effective so will continue to monitor as the time goes and days stay colder, if we get any more here in Norther CA. I doubt the long term durability of this fix but will see.

Appreciate any thoughts while I test day by day.

 

Jaguar did issue a TSB for the FEAD belt 'chirp'.
You might try to measure the brackets to see if everything is aligned.

I have fought this fault before and there were some changes to metal idler from plastic or something like that (I can't remember).

There were different belts for different years/tensioners.

bob gauff

 

I recently changed mine, no more chirp.

 

changed what?

 

Hi all, I have a 1999 xjr and there is loud chirping noise that's coming from the drivers side,mine happens when driving when warm and comes and goes with throttle movement,I have just changed the drive belt and supercharger belt,help its driving me mad.thanks in advance,Grant

 

This is what I'm getting --> chirp...chirp...chirp!!!! Only when cold.

This just started recently and would really be bummed out if it turned into something bad if I don't fix it now.

So, should I replace the belt and see if that does the trick or would I be wasting my time and money without also adjusting the tensioner and the a/c dowel? If I have a mechanic do the replacement, is it "expected" that he'd check the tensioner and a/c dowel? i.e. is that just part of the job or something specific to this Jaguar issue?

 

I am trying to attach a video or at least a link to my video that demonstrates the squeak that I hear on startup.

Here's the link

https://www.dropbox.com/s/70vcwv3wmf9xo4h/IMG_3677.MOV

I can't seem to get it to work. Please let me know if it works for you.

Thanks.

 

Mine went away when I replaced the belt and tensioner. Tensioner ain't cheap! But easy change out.

 

I hear ya, Jim! I wouldn't mind in the least spending $150 to do this job (belt and tensioner), but only if I have some reasonable assurance that it'll fix the problem. And that is why I tried to post the video just in case someone here can figure out where the squeak is coming from. I'm baffled. I've tried to lean into the engine bay and listen in different areas, but with the engine noise, it's difficult to get a feel for direction. When I drive the car before it's fully warmed up, under slight to heavy acceleration, I hear what I think is belt slippage.

Can belt slippage occur with a good tensioner and a bad belt? If so, maybe I could try replacing just the belt and see if that gets to the root of the issue (belts are pretty inexpensive). If I still have the squeak, then maybe I'd go for a tensioner replacement.

However, if anyone here says, "Hey, Mike! If you're going to go to the trouble of replacing the belt, you might as well do the tensioner at the same time!" Then I'd have a change of plan!

 

It works.

That's sounds like rhythmic metallic clicking and not belt squeal.

I'd eliminate the belt tensioner as a first possible source.

Graham

 

I apologize, OM, hadn't bothered to listen to the video. I would remove the belt (15mm socket on a long handled 1/2 inch extension for leverage) and run it for just a few seconds to see if the noise goes away. Then reinstall the belt and start hunting for the metallic reciprocating noise with a mechanic's stethoscope. Sounds stronger towards the center of the engine than right or left side, more towards the left side -- leads me to believe it is not idler, more likely tensioner, power steering, or water pump. Removing the belt rules out any bearings run by the belt (wp, ps, ac, tensioner, idler, alternator).

Not belt chirp, as Graham advised.

Again, do not rest your hand on the tube running from the radiator to the tank -- really fragile.

 

I know! And I'm saying how I know!!!!


Sorry to be such a ditz, but you confused me, Jim. If I take the belt off and the squeak goes away, what exactly have I eliminated? Belt squeal only? I know you said that taking it off rules out bearings run by the pump, so if the squeak goes away with the belt off, does that mean that it's the actual WP, PS, etc.?

 

I decided to just go ahead and order the belt and the tensioner just for good measure. Hope to have it before the weekend so I can get this little project behind me. I don't drive the car now because of this squeak.

 

Mike....that is classic belt chirp ;o)

How many miles on this car?
How old is the belt and tensioner?

Jaguar says the belt, idler pulley and tensioner are all replaced at 100,000mls
Run down there with a bright torch and inspect the condition of the idler and tensioner pulleys...if they are plastic, they are probably the originals and be quite worn.
The later updates are both metal.

Another trick....simply spray a short burst of silicon spray on the ribbed side of
the belt...noise dissapears?
It's time to replace all three as a unit, belt, idler and tensioner mechanism.

There is no adjustment on this set up as the it is automaticly spring tensioned
at a fairly high rate.
There is an actual belt wear indicator built into the right hand side of the tensioner arm.

I replaced my complete system recently and end of noise.
The idler and tensioner bearings were shot anyway.
In the real world driving, the serpentine belt system will not go 100K.... 80K is more realistic.

 

From your video, that is very similar to the sound my '05 XJR was making when cold. The noise always went away after a few minutes.

Before you replace anything, try getting a good look at the idler pulley while it is making the noise. (idler is on the lower right side, near the alternator)

On my car, I could see the belt "walking" across the smooth face of the idler puller and 'snapping' back straight. After reading about this phenomenon here on the forums, I replaced the smooth face idler pulley with one that had shoulders on it to prevent the wandering of the belt.

I just helped a buddy replace both belts on his '06 XJR that was making the same noise. Just replacing the belt in his case stopped the noise. Even though the belt ribs showed no signs of cracks, the flat side of his belt was *very* slick. I think that is what contributes to the belt walking off the pulley. A new belt has better friction, and stays in place better.

 

Hope that works; but the noise still sounds metallic (frozen bearing, maybe), not a belt chirp. Running the motor w/o the belt tells you if the noise is with something driven by the belt or internal to the motor. Once you rule out internal engine noise, a new belt and tensioner will start turning the parts driven by the belt, then a stethoscope will home in on the offending reciprocating part. Listening again, it sounds like the tensioner.

 

I just figured that with the belt being fairly inexpensive, it can't hurt to replace it since I have just over 100k miles on the car. I also figured that as long as I was at it, I'd replace the tensioner just for good measure since so many people have said theirs have gone bad. Of course, this could be the classic "throw parts at it and see if it works" method which is not the best troubleshooting plan in the world!

 

Can't go wrong with a new belt and tensioner. Probably due.

 

No mike...it isn't the 'throw parts at it' syndrome....with that mileage.it is actually due for belt and tensioner replacement as a set...and don't forget the idler pully.
They are all replaced as a unit because they all wear together and it's not good practice to throw on a new belt on old worn pulleys...unless of course you like shortening the life of the belt ;o))

 

Have a part number for the idler pulley?

Welsh has them for $55.95 but I found this one at Advance Auto Parts (on my way home!) for $19.99 -- thoughts?