W169 noise on start up

[72 dudes]

2007 A180 CDI CVT. Now the cold weather is here, I've noticed a "graunchy whine" as soon as the engine is started first thing, only at idle.

It goes off if I increase revs to 1100 RPM +.

Goes away at idle after a mile or so once engine is warming up.

Does not make the noise at ambient temperatures above 10C

Alternator bearing or belt? It's not a loud shriek like the old fan belt slip noise, more a rattly whine.

Any ideas folks?

 

[Howard]

Sounds like ours did , and it turned out to be the alternator pulley bearing.

Ours was completely shot , so we had a recon alternator put on.

Does it sound like a quiet coffee grinder ?

 

[72 dudes]

Does it sound like a quiet coffee grinder ?

Yes, not a bad description!

Sounds a likely culprit, wonder if my MB Approved Used warranty will cover it or whether it's a wear and tear item.

 

[Howard]

For reference , a recon alternator for the w168 set us back £118 + vat , a tenner for the belt and an hour for fitting so not a massive bill if it comes to it

 

[72 dudes]

Good to know, thanks Howard.

 

[72 dudes]

Quick update, it was the alternator pulley, replaced under warranty.

The bill which went to MB Warranty dept was for £330 - ouch.

Great service and I was given a new A180 CDi Sport auto as a loan car.

Nice, but lots of road noise from the comedy 18" wheels and rubber band tyres, and though the handling was sharp, it was still a bit 'wooden'.

54 MPG in my hands, good, but obviously nowhere near the 70.8 EU combined figure!