2.2d LR Disco Sport odd idle noise

[Robertb]

We’ve had a 2.2 (pre-ingenium) Discovery Sport for a few months, it’s just developed an odd noise at idle; becomes noisy, as if something is touching the engine and resonates, but there is also a squeaky chattery noise. It’s not so noticeable outside the car.

My usual garage diagnosed a worn aux belt (because the squeaky noise went when they sprayed belt lube on it) and replaced it which made no difference.

Possibly coincidentally we had a broken front spring replaced; the noise started on the way home but the garage can’t see how the two could be related.

The supplying dealer changed the cam belt and water pump before sale. Could it be a faulty pump?

Otherwise the car works fine and the noise stops as soon as the revs rise from idle.

Any thoughts gratefully received other than
-well it’s JLR what did you expect
-it’s a 4 cyl diesel they all sound like that.

Edited by Robertb on Wednesday 19th March 07:21

[paul_c123]

1) What is "belt lube"?

2) I'd more likely suspect its the bearings or some other rotating component in one of the accessories, ie alternator, air con compressor, etc.

I imagine their "belt lube" was WD40 and they got it onto the failing bearing, which temporarily quietened it down. I don't know if the water pump is driven off the aux belt or the cambelt, but if its the cambelt I imagine that's behind a cover so never got sprayed in the process. It might be the water pump but seeing as the spray quietened it, unlikely....

[Richard-D]

I also would expect the noise to be coming from a bearing on the accessory drive side. Could be a tensioner, idler or any of the accessories. I would remove the belt and carefully feel for play and/or roughness in everything on that side.

[255SNK]

A worn belt tensioner or AC compressor pulley were my first thoughts...does the noise disappear if you turn the AC off?

[stevemcs]

Alternator pulley can chatter when knackered.

[Robertb]

Thanks folks, some very useful ideas.
Yes it was just some spray lube, I think just to help them diagnose where the noise might be from.

The AC does not affect the noise.

It’s going in to the supplying dealer tomorrow so I’ll get them to check the various pulleys and ancillaries inc the alternator.

[stevemcs]

Alternator pulley can chatter when knackered.

[Robertb]

So, went back to the dealer today, who couldn’t find anything wrong with it.

Either they’re deaf, or lazy. The latter I suspect.

So that’s two garages who’ve failed.

Effing useless. Wish I knew of a decent mechanic.