Hi there,

My girlfriends 02 Seicento Sporting has been making a mild grinding/rattling sound (difficult to describe) over the past week or so and I'm not sure what it could be.

It doesn't increase simultaneously with rpm, although it does appear to be worse at higher speed. It doesn't seem consistent with engine revs at all though.

I had a listen under the bonnet and as much as I can tell, it sounds like it's coming from the alternator.

First thing I thought was alternator bearings, could this be it? Or is it likely something else?

The alternator is obviously working fine as I ran the battery flat a week or so ago while installing a CD player and playing around with it for too long without the engine running and 5 minutes after a jump start, it was back to normal, and had no probs whatsoever since then.

If it is the alternator, how soon should it be looked at? We were gonna be driving it about 150 miles at the weekend but if that's a bad idea then we probably wont!

Many thanks

Does it go away with the clutch pressed in (if so its the release bearing)...

If its gearbox noise, it could be gear chatter (which is a replacement job)...

Bearing usually whine from experience...

If it was the alternator i would be sure it would increase with revs as the belt runs off the bottom pully...

Just check for loose metal parts, like inspection plates etc.

Yeah I see your point, I guess the noise would worsen with revs if it was definitely the alternator.

Just tried it with the clutch in, noise still exists.

It also doesn't appear to be linked to engine revs, it does get slightly louder at higher revs but the noise doesn't get 'faster' if you see what I mean.

It also sounds the same through all the gears.

Hmmm strange one!

Dead easy check. Take the alternator belt off. Drive the car. Is the noise still there.

Other known noise sources from that end of the engine are water pump and belt tensioner. I guess the tensioner will be about three and a bit years old, so less than a year away from replacment, but it could have failed a bit early.

Cheers

SPD

cov69 said:

Does it go away with the clutch pressed in (if so its the release bearing)...

Click to expand...

Or low/no gearbox oil

Thanks for the replies.

How do I go about taking the belt off?

I remember on a Punto I had it was a case of loosening the nut on the top in the slot that sets it's tension, and then I seen to remember another bolt that pressed against the cog or something (it was a while ago )

thanks

could it be one of the heat shield on the manifold or another part of the exhaust system. they really make a noise when loose

It could well be. And I hope it is!

To be honest it is pretty difficult to tell exactly where it's coming from. It was also pretty dark when I checked. I will check again tomorrow and remove the alternator belt if necessary.

I read on another post here that the engine mount makes one of the bolts inaccessible without removing it, is this the bolt on the tensioner?

Changing the alternator is helped by undoing the engine mount, removing the belt doesn't.

Cheers

SPD

rallycinq said:

Changing the alternator is helped by undoing the engine mount, removing the belt doesn't.

Cheers

SPD

Click to expand...

The alternator will work even if the cooling fins are grinding into the casing...

Before you remove the belt try rocking the belt driven piece it should not move radially some slight axial play might be allowable.

If it is noisy it may be very loose.

If it has been noisy for a while I'd get an exchange rather then a rebuild.

Noel

probably same as my noise timing chain has either stretched a little ofr little wear on tensioners not much you can do.

cwc2128 said:

probably same as my noise timing chain has either stretched a little ofr little wear on tensioners not much you can do.

Click to expand...

This is depressing.

The 1108 has a timing belt and a tensioner (essentially a large, sealed, bearing race) which require periodic replacement.

The 899 has a timing chain (but not, IIRC, a tensioner) which after extreme mileages can become worn. I believe that replacement chains may no longer be available from FIAT, but any roller chain supplier should be able to supply an equivalent. If the sprockets are worn they could be built up with weld and re-machined. This is probably less economical than swapping the engine out.

To discover where a noise is coming from, use an engine stethescope or a long screwdriver (blunt end to ear!) as a stethescope.