Fan

My fan is make a big noise, you now if i need change only the motor or the complete fan to eliminate the problem?

is it coming from your electric auxiliary fan or your main engine fan? is it a whooshing noise like a big rig truck or bus, or something else? when does it happen in relation to engine temperature/RPM/car speed, and how long does it last before it quiets down if at all?

I have the same problem. it is coming from the AUx fan. The fan comes on randomly, it could sitting in neutral or driving. It sounds like a very stressful revving sound and then it goes off. My mechanic checked it with the BMW scanner and a fan issue showed up. The car does not over heat, I just changed the water pump and radiator too. I noticed this before I did the radiator but after the water pump. Any idea of what I should do? I thought it might be the resisters of the motor??

I've experienced this issue on the 2003 E39 530i.

For me, the problem occurs when driving in slow traffic (5-10mph) for 10-15 mins. It also happens if I keep the car running in Park position (so the car is not moving) for about 5-10 mins. This usually happens at low RPM, ~1000-1500.

The fan start spinning violently and I hear the noise inside. From outside it is very very loud like a huge truck.

I do not experience these loud fan noise when driving at highway speeds (60-80mph). May be because fan noise blend into other highway noises.

The temperature gauge does not fluctuate. It remains normals.

I purchased the car used with not much history. I do not know if the previous owner replaced radiator or waterpump.

Any suggestions?

exact same with me and have not yet figured it out, but i recently changed my water pump and radiator so I don't know what it is now?? going to see a friend that was a certified BMW tech next week. I'll let you know what he says. If you find out first please let me know.