Technical Clatter Clatter, what now !

[Multiporter]

Well its 2 weeks since anything went wrong with my beloved 51 reg diesel Multi, 90,000 miles good service history.
Started her this morning and there was hell of a clattering noise under the bonnet (bit like two spanners in a biscuit tin)
No engine warning lights appeared and oil level is good on dipstick.
lifted the bonnet and couldnt locate the noise exactly but seems to be in the cambelt area (this was replaced 3 weeks ago plus waterpump and tensioner ect)
As I looked at the engine the noise subsided and then disappeared completely.
I turned her off, left her for a few hours and then restarted, same loud clattering which gradually quietened over 5 minutes and then disappeared .
Engine is running sweet car drives fine.
What the hell could be causing that sort of noise which then disappears.
Really appreciate your advice please guys thanks

P.S thought I was imagining it but have felt some reasonable vibration on tickover the last few days before the noise appeared

 

[widemouthfrog]

Check your crankshaft pulley - look at the rubber centre and see if it's delaminating.

It's easier to get a good look at it by removing the inspection panel on the inner wheel arch (drivers side).

 

[boilermansab]

Oh yes..exactly what happen to me!
You could also look in engine bay with engine running and look down left hand side at the auxilary belt and you will see the pulley at the bottom, it should be spinning with no lateral movement...
Looking at £50-60 just for the pulley if its that...

 

[Multiporter]

Thanks for the info guys, I will check if this was replaced when the cambelt was done, could be a faulty one, In the mean time I need the car, can I run it ok, as the noise does go away, or is there a risk of serious damage ?

 

[boilermansab]

Well I don't think I'd run the car if it is the pulley...
Mine made a right mess of it self after just 10 miles...it was only 13months old and a genuine fiat part!

 

[widemouthfrog]

Just to be clear - it's the pulley for the auxillary belt, not the timing belt. Have a look at it and see what shape it's in. If the aux belt lets go, it can take out the timing belt cover and a couple of other bits and pieces. If you can avoid it, I wouldn't use the car.

At least it's an easy thing to replace. Decent quality new ones can be had on ebay for £40-45, delivered. Make sure when you buy one though, that you've got the right length bolts (4 needed). Older cars have a fatter pulley that takes long bolts. Most of the replacements for sale have a more recessed centre and the long bolts bottom out in their holes before they tighten on the pulley. Some sellers can provide a set of shorter bolts.

 

[Multiporter]

Thanks Widemouth, I've been trying to explain to my father in law mechanic over the phone about the problem, he kept saying are you sure its the crank pulley ? Your advice has helped clarify it, I will have to drive the car a short way to him as he has all the right workshop stuff, do you have any idea why the noise subsides after a few minutes ?

 

[widemouthfrog]

No, but that's often the way it is. The noise usually dies away as engine revs rise. A failing pulley can also give rise to odd vibrations that almost feel like cluch judder.

Give the pulley a close look. With the inner wheelarch panel off, it's easy to examine. It may not be the problem! Check the tensioner for the aux belt as well. If it looks like its' spindle isn't pointing dead across the line of the belt, that could be shot, though normally you'll get a squealing if that's on its way out.