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It is possible that the bottom crank pulley / damper has failed but its easy enough to check...
They need to have the engine idling and then turn the steering wheel fully over to one one side and hold it there - if the belt is seen to jump badly / skipping on the pulley, then the pulley is at fault. The pulley will be seen to be rotating per normal in the middle where its firmly attached whatever....its the outer rim / centre that comes apart so thats how to tell - have them carry that out to see.
To be honest, its 99.9 % likely to be that as this is a known fault - there is even a Jaguar TSB - Technical service bulletin on this fault - which I will give you following ...
Too - its obvious that the noise will be louder with the AC on...simply because its putting more strain on the belt / pulley.
As the TSB points out , there are modified parts available which you will need to get from a Jaguar parts dept , to cure this for you ....
So yes, it will be that bottom pulley... Here is the Jaguar TSB for you :BulletinExcessive noise / movement from drive belt at idle / under load
- Excessive noise from auxiliary drive belt at idle, under load.
- Poor manufacture of crankshaft damper/pulley.
|Crankshaft damper/pulley|| C2S 51547 ||1|
- Check crankshaft damper/pulley number. If crankshaft damper/pulley has part number 4C1Q-XXXXX-C1A, 4C1Q-XXXXX-C1B, 4C1Q-XXXXX-CDB or 4C1Q-XXXXX-CDC, it must be replaced.
- Fit modified crankshaft damper/pulley. Use special tool: 303-D055. Tighten crankshaft damper/pulley bolts to 45 Nm + 120°.
- Fit modified auxiliary drive belt tensioner.
- Fit modified auxiliary drive belt.
I sincerely XXXXX XXXXX above all helps you and helps with the understanding of the problem you have -and what needs to be done to cure this ...
Kind Rgds, MIKE.
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