So A bit of a long shot. I have 2013 sdv8 4.4. Which for the past 6months or more keeps throwing the aux belt. This all started 9months after replacing the alternator. Things that have been tried so far are:

Second alternator.
Water Pump.
Tensioner x 2
Idlers X 2

So far no change what so ever.
Symptoms: Start the car and you can hear a clicking noise. On every click the belt moves 1 - 1.5 cm on the bottom idle pulley. If I leave the car the click goes and I have no further issues with belt movement. If I have not waited for the clicks to finish then the belt may or may not fall off.

There are no issue with starting and as I said once running it will do so for the rest of the day. Only when left for 7-8 hrs does the problem reoccur.

Don’t know about the L405 but when getting a new belt for my L322 I found that there were two different possibilities. The difference was that one belt had fewer grooves. Wonder if that could be a possibility? John
2008 Stornoway Grey 3.6 Tdv8 Vogue
2005 TD6 Java Black Vogue - Written off!!
GAP iiD BT
2003 Discovery TD5 Auto, Nanocom Evolution - gone to a new home!
MasseyFerguson 152 - No electronics!! - Sold

Hi thanks for the reply. But as far as I know this is only a 6toothed belt pk6 . The total length can be +- 5mm . It started with a gates belt which was 2498mm and currently I have an INA belt which is 2500mm. This one has yet to fall off. But mainly as I am waiting longer before I set off. The car is booked in to an indi but earliest appointment is 5th September.

It sounds like something wasn't properly aligned when the alternator was fitted. The Gates 6PK2500 is a good belt. I have the same one on mine. Kev

2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

From what I have read, that would be my conclusion. However the alternator has been replaced since then and also it ran for 9 months before it started falling off. After a minute or so the belt runs true. It only jumps on the clicking sound.

Genuine or after market tensioner? Some after market ones have been reported to be sloppy from new.

I have tried both oe and aftermarket.
The results were the same.

I'd take the belt off and get a straight edge to make sure all the pulley faces align.
Check the water pump has no play. Could the water pump be the source of the clicking? After 5 minutes of running it might have expanded enough with the heat of the water to get a clearance gap again.

Hi Thanks for the reply.

I have changed the water pump. the clicking was therebefore and no change after. The time it takes for the clicking to disappear is less than a minute. So would have no chance to warm up enough to affect anything there. This is why this is so confusing and difficult to find. I also tried the straight edge, but again nothing seems out of alignment. Also if it was why, would it after the minute all re-align. My own thoughts at the moment are the aircon compressor. But if this is off with the climate control why would be trying to engage at startup and then why would it not continue when compressor goes on and off. I think the gas levels are low at the minute 925Kpa. but would this affect the system and possibly cause it to switch (Click) ?

I consider that mine's clicking it due to the join in the belt. As soon as the belt softens it becomes more flexible so doesn't cause the tensioner to jump.

Have you watched how close the belt runs to the front of the tensioner pulley when cold and if it moves back once warm?

Hi. These modern belts are fairly seamless and I have had to change 2 or 3 now. Again, no difference even when the belts are different lengths or manufacture. Also only used Gates and INA. As for the movement of the belt , this is as mentioned in my first post.

Start the car and you can hear a clicking noise. On every click the belt moves 1 - 1.5 cm (in and out) on the bottom idle pulley.

This is the pulley by the alternator and straight after the tensioner. There is very little movement of the belt, on the tensioner pulley.

No offence intended, just it’s best to start with the basics, are you 100% sure the belt is routed correctly? Then check alignment, check faces of pulleys are all parallel, then check belt tension.


[img]https://www.fullfatrr.com/gallery/albums/userpics/24757/normal_IMG_0850.jpeg[/img]

A short video might help us.

haha no offence taken.

Any help on this would be great.

Here are 2 videos from startup. Not a great, but you can see the belt jump on the click.

https://youtu.be/toMix3Jzgd0

this second video was from a few months back.

https://youtu.be/RvYQf-N_bjE

Sounds like you have a squeeky pulley bearing somewhere. Have you changed ALL the pulleys?

I have had all idle pulleys and the tensioner replaced. The squealing is actually a new noise within the last week or 2. I have not changed the Active cornering pump or the compressor. My feelings were these are too far away from where the problem is occurring. But more than happy to be proved wrong.