Mercury Cougar makes awful noise

My 00 Merc. Cougar makes a noise like a leaf blower, whenever it feels like it. It only happens in cold weather. Recently it has also started to hesitate and stall when I am idleing and it starts to make that noise.

I took it in last winter and the mechanic checked the fan and fan housing and said her could find nothing wrong. of course, it refused to make the noise for the mechanic! I read the discussion about stalling and additives…would this help me? Looking of course for the cheap fix! I am nearly totally ignorant of cars etc. Thanks, Cath

You can tell more about the symptoms, can’t you? Is the leaf-blower sound of an electric, or a gasoline, powered leaf blower? Is the sound a steady, high pitched, tone? How cold is the weather when it happen? Does it occur when the car is moving? At what speed?

Alternator bearings can pick and choose the time to screech.

Someone said it is the “moose” sound, so I think it is more like a gas blower, It is pretty steady, not high pitched, it lasts for up to a couple of minutes at a time, stops, comes back 10-15 minutes later. If I turn the engine off and back on again, it stops…until it feels like doing it again! Yesterday it got up to 53 and it didn’t do it at all. It does happen at all speeds and in all gears. It is loud enough that people near my car take a look to see what is going on!