I have a 92 325is and i have heard this whine simmilar to the sound of a supercharger. it has caused my car to overheat a few times. Lately, this sound changed from a whine to a rapid very loud tick, and still overheats in city driving. It will not overheat when i'm driving constantly in the highway. the sound only comes on when the car is moving and gets louder as i accelerate. The other day, i took all the belts off my car so the pullies are not at work and drove the car up and down my street and it still makes that sound. I have no idea what this could be. If you have any idea what this could be, please let me know. I thought it was a pully at first but since i removed the belts and the pullies were not spinning when i drove the car for a little and it still made the ticking, i don't think it could be a pully. Any input is appreciated.

i;m guessing the whine is/was your water pump dying - i wonder if it self-destructed and the ticking is the sound of bits of it in the engine.

AHHHHH. that actually makes a lot of sense. But what about the car overheating in city driving, and not overheating on the highway (or constant rpm)

If it's the water pump, like i thought as well, on the highway there's more air flowing through the engine compartment.

whinning sound check alternator... mine was doing same thing and when closely examined it was the alternator... overheating I've read that was air in your system.

Just had alternator replaced not too long ago, no symptoms of battery problems either. Also, no air in my system; not cooling related on this problem, it has to be a malfunction with one of the components.

Your Aux fan is probably inop or dying. The ticking is most likely the fan hitting something. That is why it overheats in town and not on the road...

That was on my mind, but it shouldn't cause my car to overheat. Afterall, i am in San francisco, where a good day is 65degrees.

If you have a '92 and you haven't replaced the water pump in recent memory you really should just go ahead and replace it, and flush the coolant system out really well. I wouldn't drive again till that was done, if I were you.

with belts off you would not be turning water pump or fan, so the fact that you continue to hear noise is odd. Are you sure it is not valves/lifters? (head problems due to overheating?

Overheating in city driving could be water pump, T-stat, fan clutch.....
agreed - fix that ASAP!

I can do that for/with you if you want, although I am down in south bay.

Hey thumper, thanks for the offer but i have taken apart and put my car back together dozens of times; might need an extra hand for the near future turbo mods:). Anyhow, this thing is driving me nuts. It went from a whine to a tick; doesn't sound like a motor problem. I also agree that it is very weird that the sound only occurs when the car is in motion, and with the belts off and still making the noise is really starting to piss me off. The fact that the car did overheat and sounded like it was a pully problem; my cooling system is fine; everything is good; so i have no idea what to do now.

Also, doubt it is the motor as the car only makes that sound when in motion. when i rev the motor in a still position, there is no tick or whine.