[Andy1984335i]

Omg everyone guessing only one of 30 answer it was right.

Redlineclipse go get u self a new battery bro and that is gonna put a big smile in you face the battery is too weak to make the water pump work with the right voltage

[Andy1984335i]

I'm having exactly the same problem and if you want to see if I'm right if tha happen again before you put the new battery disconnect the negative terminal of the battery and im pretty sure the car is gonna stop overheating and the heat start working again and if doesn't happen after first time try a second time but the same thing happen to me I'm gonna geta new battery today

[Tyc0]

For anyone who's hasn't already replaced your water pump or thermostat, just do it. I had the exact same issue as OP, turns out my water pump was only running about 2/3 power, but I thought it was fine because when I did the bleed test that ran the pump it sounded healthy. So just replace the pump and thermostat and worst case it doesn't fix it and you've done preventative maintenance.

[rontan]

hi guys. my car is having the same issue.
i will be sending my car to the workshop this afternoon.
i will share the result with all of u once the error fixed.

E90 N46B20 non-LCI 2008

[rontan]

hi guys,
the workshop has just sent the car back to me.
after checking, no issue on water pump, radiator fan and radiator. no leakage.
the mechanic has done the coolant adaptation and is now no longer has engine overheating problem during slow traffic.
he did for me free of charge.

[rontan]

hi guys,
the overheating came back again this morning. it has nth to do with coolant adaptation which done by the workshop few days ago. i managed to find out the cause and i have solve it myself.
i will start a new topic with E90 N46B20 Engine Overheating Problem and Solution.
Thanks.