Advice welcome....

[Lloyd]

Mine does the exact same. Is this correct?

Yes, all ok in that department AFAIK!

[Keith]

Mine does the exact same. Is this correct?

yep..... it's OK with it.

[Lloyd]

Right, first off big thanks for advice received so far everyone.

Had a good look at the problem today and have an update.

Initially, started car from cold and had a go at removing the oil filler cap
and listening for any change in the noise. I could hear the cam chain much
better but clearly was not responsible for the rattle.... (good tip!)

Then had a go at dropping off the PAS pump belt and re-starting the car.
With the PAS pump disconnected the rattly noise was still evident.

We also measured the axial float on the pump as 0.5 mm, which from searching
on the forum indicates it's still in good order.

(worst documented axial 'float' on this forum is 4 - 5 mm! )

From inspection the rattle appeared to be originating from the central belt pulley on the crankshaft. The one with the three belts on.

We then poured some water on the crank belt pulley and the noise stopped immediately. After a short while the noise came back. We found that dripping the smallest amount of water on this pulley stopped the rattle, albeit for just 20 secs or so....

What is this pulley? Is this the vibration damper? Has anyone any experience of this wearing/breaking/rattling like this?

the crazy thing is that the rattle sounds very metallic and yet just a tiny amount of water stops it right away. The more water poured on the longer before it rattles again.

Be grateful for any further suggestions/advice on the matter chaps.

Cheers,

[220bhp]

You need to check this,if its loose or the woodruff key is sheared it will disstroy your engine.the crank pulley is bolted to the end of the crank by the crank bolt 27mm I think,this is touqued to around 350 to 400nm but the damper is connected to the pulley by four smaller bolts,check the security of these for bolts,and for any thing that may have got trapped in the bottom casing,ie a spacer or washer

[Knight Rider S4]

Looks like you will be taking the bumper and intercooler off to get access to the pulley big trouble if the woodruff key shears £££££........so best get fixed ASAP

[Pirvu Eugen]

Check also the alternator. If an bearing is gone can make this noise. try disconnect the alternator belt for testing. I know that you have to disconnect all the belts before that one. Also the clima compressor bearing. I had that before but dont neglect the timing!!!! If that big bolt was not tightened ok then you can damage the engine. Anyhow, the tapets are on the way out because they ratle at startup a little bit, dont wory.
Hope that helps!
Eugen

[Lloyd]

Thanks for the advice chaps.

Have got the car booked into APS this Wednesday to get it sorted.
Not sounding like an amateurs repair job. Will not drive it anymore
then absolutely necessary to get it there...

The car has only covered 58,000 miles so is disappointing this problem
has arose...

The car had a cam belt change at the 10 year point as per service plan.
I wonder if the garage simply re-used the wooddruff key and crank bolt?

Can't get over how a tiny amount of water poured onto the pulley - and i do mean tiny, like 2 drops! - can stop this metallic rattly noise immediately. Albeit, for a few tens of seconds....

[GT500]

Good you have narrowed it down!
Not heard of a damper causing trouble, The woodruf key is part of the cam belt pulley, not a separate part, if they tightend the pulley bolt by holding it on the brakes or stopping the flywheel truning, all the force of the big torque on the bolt can crack the the woodruf on the pulley. They need to replace the pulley (about £25.00) and use a crank pulley tool that holds the damper to tighten the big bolt.The little key isn't up to holding all the torque of the tightening process.

The dampers are £360, I doubt it will be the problem.

[Lloyd]

Result!

I think I've fixed it!

Spent much of Sunday working on the car. Removed the front bumper, IC and changed the auxiliary belts. Couldn't tamper with the cam belt/pulley at home so left it at that.
I didn't really beleive that changing the A/C, PAS and Alternator belts would make any difference but felt like I should replace SOMETHING whilst I had the bumper off etc.

Whilst I was at it gave the car an oil change and fixed a boost leak (split hose by the throttle body - thanks Doug for the spare!). By heck, she flies now!!

Corey, you were bang on about the car not boosting quite right earlier this year!

Anyway, this morning, starting from cold (acid test) no rattles at all from the engine bay. ...

How can worn belts be responsible for making a metalic rattling sound? I can't seem to figure it out. Anyway, not I'm not complaining!