Fan that makes a noise like a truck

[Sambo1]

Hi , I have a 1996 525i, when I pull of from the traffic lights after I have been sitting for a little while (longer than a couple of minutes) the car sounds like a big truck taking off. The fan is very loud and it makes a louder noise that normal. This will only do thia while the car has been idleing in traffic. After around 20 meters of driving the fan noise goes back to normal. Has any one heard of/or had a similar problem.

PS the car is an automatic.

Thanks.

[csieminski]

I don't know why this is, but I just bought a 1990 535i automatic, and mine does the same thing. Do you have the A/C on when this happens? I do, and it might have to do with that, although like you said it sounds like it's the cooling fan. Same thing--I'll sit at a light for a minute or so, and when I press the gas to take off, there's a muted roaring sound that cuts off after the first 75 feet/5 seconds of acceleration.

This is not any kind of expert opinion, but I don't feel this is too out of the ordinary. Try shutting the A/C off, or observe what happens if it's cooler outside.