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I've never seen anything like that before. I don't see how it's possible unless a belt has been fitted with one less groove as several of the pulleys including the alternator and the replacement spec idler pulley have raised ridges at either side. How could be belt ride over those ridges unless the tensioner was completely shot, in which case the squealing would be the most obvious symptom. The belt is available with an alternative number of ridges.
The Jaguar belt is a standard Dayco and is the same as the Gates and as far as I can see.
Richard
Richard
1999 XKR as in the short video.
After changing the valley pipes, whilst the belts were off I thought it prudent to change the serpentine belt for a new one. I bought a Draco belt (bottom belt in the photo) which jumped up and down the pulley as shown. I refitted the Jag belt and all was well. Both belts have the same number of grooves but the Jag belt has deeper grooves than the Draco belt.
Just reporting what happened to me.
The Draco belt (bottom in picture) actually managed to have I groove sliced off it when fitted!!
You can see the difference in depth of grooves.
Richard
1999 XKR as in the short video.
After changing the valley pipes, whilst the belts were off I thought it prudent to change the serpentine belt for a new one. I bought a Draco belt (bottom belt in the photo) which jumped up and down the pulley as shown. I refitted the Jag belt and all was well. Both belts have the same number of grooves but the Jag belt has deeper grooves than the Draco belt.
Just reporting what happened to me.
The Draco belt (bottom in picture) actually managed to have I groove sliced off it when fitted!!
You can see the difference in depth of grooves.
I have never heard of Draco belts and I have never seen a belt with such flat ridges when new.
The original Jaguar belts for the X150 were made by Dayco and were 7 ridge as in your photo. All the automotive polyvee from all manufacturers have the same ridge profile.
Your Draco belt shown above only has 6 ridges and the jumping belt shown in your video also has 6 ridges. I do not believe that a ridge can be sliced off a correctly sized 7 ridge belt cleanly like that just by running the engine.
May I respectfully suggest that this is either a wind-up or you have accidentally fitted a 6 ridge belt with inevitable consequences. 😉
Richard I am only trying to help Tek UK. Did you actually watch the video I posted above of the belt snaking and jumping?Ok Dayco, not Draco but I promise you I am not winding anyone up. Why would I do that? This is the belt that caused to problem. Dayco belt.
Last edited by Neville Hobbs; Mar 11, 2023 at 08:14 AM.
Richard I am only trying to help Tek UK. Did you actually watch the video I posted above of the belt snaking and jumping?Ok Dayco, not Draco but I promise you I am not winding anyone up. Why would I do that?
This is the belt that caused to problem.
Dayco belt.
As I said, the Jaguar OEM belt is made by Dayco and the two are identical and the rib profile is exactly the same. There is no such thing as a "Jaguar deep grooved belt".
If your Dayco belt had the flattened off ridges are shown in your photo then it was either not a genuine Dayco or it had been used or damaged or something similar before you even received it. The fact that it appears to have lost a ridge so easily makes me suspect it was a counterfeit belt. Remember the the Jaguar OEM belts are simply Jaguar branded Dayco belts. If you compare them side by side when new you will see that they are identical.
In any event, this is not the OP's problem. A belt which is jumping such as in your photo, and the only time I have ever seen that in 55 years of stripping down engines was when a belt was fitted incorrectly, would not sometimes do a few jumps every morning and then be fine for the rest of the day.
Richard
Last edited by RichardS; Mar 11, 2023 at 11:12 AM.
There are two different issues on this thread.
VVT and belt.
Richard, sounds like you are always right so you probably are.
Perhaps the Dayco belt was a copy. I have no idea, however, it made that clacking noise when cold and had a rib stripped in no time. Jaguar stamped belt cured the clacking.
Just looked up where Draco belt came from. British Parts!!! I do know that they sell copy parts sp perhaps it was poor quality. It was only £10.90. I never buy from British Parts any more after faulty banana arms which have solid rubber main bushes, not hydrabushes which they should have.
Hi all, thanks a lot for all the comments.
2 clarifications which might help:
I've owned the car since it had 40k on the clock (now 100) and to my knowledge, the belt has never been changed (unless by prior owner) but will double check invoices.
I wanted to investigate further this week end but it has not done it again. It would seem that it only does it when the weather is cold like <5 Celsius (and the car too), like first thing in the morning.
I started it Saturday mid day (it was about 9 C) and evening and likewise yesterday and no noise...
Hi all, thanks a lot for all the comments.
2 clarifications which might help:
I've owned the car since it had 40k on the clock (now 100) and to my knowledge, the belt has never been changed (unless by prior owner) but will double check invoices.
I wanted to investigate further this week end but it has not done it again. It would seem that it only does it when the weather is cold like <5 Celsius (and the car too), like first thing in the morning.
I started it Saturday mid day (it was about 9 C) and evening and likewise yesterday and no noise...
The recommended change interval is 150k but at 100k I would probably change the belt if it has never been done unless it looks to be in perfect condition. If there is any sign of cracking on the ribs then the next service would be a good time to get it done, although they will run for thousands of miles with a small crack or two every couple of inches. Splits on the smooth side of the belt are more serious and would warrant a belt change.
