my 2001 e39 530i sport seems to be overheating.....well it might not be, last night quite suddenly the temp gauge was in the red, switched the car off kept ignition on so the fan could do its work but nada, the fan wasnt doing anything. Checked the temp, still high, watched it fall after a few mins but it took around 15-20 secs to fall to midway and stopped bang on mid way point. opened up rad put a little top up of water in and started car up again and let it run. Left for a few mins and watched it, still didnt move from mid point. drove home again watching the thing like a hawk.

About halfway home (10 miles) it shot up again to red and back down to mid point all in the space of 20 secs ish?? Kept going......nearly home and it started doing it again, doesnt seem to be overheating could it be a thermostat, switch etc.

I replaced the radiator last month due to a crack in the plastic housing, maybe another fault somewhere???

I am just about to go out and let it run in the drive to see what happens, but thought i would run it by you guys first....