4k rattle - not the usual thread.

[Ex-User (107751)]

I'm getting a very loud rattle around 4k revs, doesn't matter if I'm on/off throttle or in gear.
The noise is clearly coming from the timing / aux belt area and not from under the car (so I rule out the mid section). It's been the same for the last 6 months.
It's not the heatshields, cat to manifold springs, loose alternator bar / injectors cover. Maybe some tool or bolt got stuck in that area while working on the car.
Can you suggest what should I check, where could something get stuck?

 

[James363]

It could be the aux belt tensioner. They are only really designed to last as long as the belt, so if not replaced at the same time, they can go, causing a rattle.

 

[Ex-User (107751)]

It has less than 3 years... Any way to inspect it and the other pulleys ?

 

[James363]

Ideally, you want to check any pulleys the belt goes over for any wobbling while the engine is running, but rattles like this can be a b**ch to trace, as you can't always see the problem, and the pulleys themselves are hard to get a good look at.

 

[Ex-User (107751)]

There won't be any visible wobbling I'm sure... Also like you said it isn't accessible while the engine is running

 

[James363]

Well the other option is to have as much of it apart as possible and feel for play in the bearings, same procedure as feeling for play in wheel bearings. I think the tensioner is the most likely culprit, so I'd start with that. If it's rattling loud enough to be heard over the engine, there should be considerable play. Obviously this assumes it is nothing to do with a heat shield/cable/anything else rattling. If it's a loose bolt or tool dropped when working on the car, no one on here will know where it is.

 

[Ex-User (107751)]

Here is a video of the noise. Really looking forward to sort this !

 

[LeeRS]

Sounds like heat shield to me.

 

[Ex-User (107751)]

Had them all removed already .

 

[LeeRS]

Do you have a MAD battery cover?
Only ask as mine worked loose and did vibrate.

 

[Ex-User (107751)]

No cover :wink:

 

[Mr Plums]

Has your ecu cover bracket snapped?

 

[Ex-User (107751)]

Yes but it's not the cause unfortunately

 

[Mr Plums]

Cant you get someone to hold your revs at 4k while you locate the vibrator?