I'm going to have to check my receipt for the work done as they may have just changed the pulley on the tensioner and not the tensioner itself. A weak tensioner would certainly be a root cause of slight belt slippage when the belt is cold. 2012 TDV8 Vogue (L322)

I had another look at this over the weekend. I cannot pin point the chirp, but it certainly sounds like it’s near the alternator.
I have visually examined everything touching the aux belt and see no signs of movement or wobble.

My next step is to remove the fan and cowling to be able to gain better access. It’s a ball ache… but not much choice really. Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

I had my belt and tensioner changed last week and oh what joy - no belt noise on startup in the morning. No idea if it was the tensioner gone weak or belt contamination and neither did the garage but it's fixed after putting up with it for nearly a year. 2012 TDV8 Vogue (L322)

My culprit was the idle pulley that sits on the bracket at top left of the engine. Bearing was shot Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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Mine squeaks of a morning yet all pulleys, the tensioner and both belts were replaced a few months ago. It sounds like a failing bearing in a small pulley.

Squirt some water on the belt - this will tell you straight away if it's a tensioner bearing or not 2012 TDV8 Vogue (L322)

I intend doing that if I think of it when not on my way out.

Edit: Mine's noise is caused by the belt. It has a short wobble section, presumably at the join, which is interfering with the smooth passage over 1 pulley. I haven't determined exatly which pulley yet but I suspect a smooth one that runs on the back of the belt.

JayGee wrote:

Squirt some water on the belt - this will tell you straight away if it's a tensioner bearing or not

Worth trying brake cleaner but it didn’t fix mine. It could also be the tensioner not putting enough force on the belt to create enough friction. As I had both changed I never knew.. 2012 TDV8 Vogue (L322)

No time like the present!
Just been and given the belt a liberal dosing of degreaser. As soon as the first squirt hit the belt the noise disappeared. It was a blissful diesel grumble. I let the engine run for a bit to get in all parts of the components, and now to sit for a night. I’ll try repeating over the next few days to see how I get on.

If not, I will plant to dismantle to gain access, remove the belt, see what parts look good or bad and then go from there.

@JayGee, did you clean anything before fitting your new belt? Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

The noise always returned the next morning with mine. Got the garage to change the belt and tensioner but they did clean up the mess left by the belt dressing I’d used  2012 TDV8 Vogue (L322)

So far so good…
Last night I took the car out and there was no squeal!
Let’s see how it goes over the next few weeks… if I need to spray it every so often, I’ll put up with that until the warmer weather returns next year!

At least this suggests belt contamination rather that a problem pulley or bracket  Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

 2012 TDV8 Vogue (L322)

It’s not quite the magic fix I’d like… closer, but not perfect.

Starting the car is fine. Nothing but the normal TDV8 grumble. As I drive down the road with the still cold engine, I get 20 meters and a squeal returns but less intense than before and is only there above 1,500 rpm. I stop at the end of my road it goes, then squeals as I pull away.

Less than a mile into my journey and all is good again. It’s just that initial cold start and only above a gentle squeeze of the go pedal.

I’m continuing to spray with degreaser, but only use the car once or twice a week now so it’s not forefront of my mind therefore I often forget until that 20m point. When I do use it, all is good for a couple of days or journeys.

Oh, and the bottle of degreaser is ironically covered in oil… I don’t want to get my hands dirty  Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

This happens to my 2011. It only happens when it's very very very cold. Will go away in 15 minutes. Doesn't happen any other time of the year.