406 Hdi. Electric motor running?

At first I thought the cooling fan was running but not so.The noise seems
to come from back/side of the engine near the alternator, the noise will
stop after several minutes or by switching off the engine and re-starting.
I've only been aware of the noise five times in the last 12,ooo miles when
driving in town traffic, but it could be happening at faster speeds when
the overall noise level is higher. The car is four years old and has AC
and done 96,500 miles.

 

Possubly alternator brushers bearings wearing out

 

Get a long screwdriver, stick the handle against your ear. and the blade
onto the alternator, you will hear if it sounds rough. Then try the blade
against other parts in that area and see which one sounds worst.
Does this only happen at low revs? It sounds to me as if it might be the
auxiliary belt tensioner. They do rattle a bit at about 1200rpm. When I
complained to the dealer when mine was under warranty, I was told it was not
unusual for this model. Indeed, the engine has now done a further 50,000
miles, and it still sounds the same.