Whinning Noise For Heater

[Real_Hunter]

C-CLASS: When I turn the heater fan ON either via the fan speed control switch or via AUTO selection a "whinning" noise can be heard from the vents. I looked under the bonnet to see anything obviously loose or to detect as to where the noice was comming form, but no luck. The noise stops when I switch the heater fan OFF.
Any suggestions welcome.

 

[stats007]

No idea about a C class but the fan motor on a R107 always went wrong like this. WD40 on the armature etc helped but it always came back until you replaced it with a new unit.

 

[Shude]

Mine wheezes from time to time due to worn brushes! The noise disappears at full speed though. St00pid brushes