I've got an auto 2000 E46 318i. I replaced the radiator due to a coolant leak yesterday. I flushed and bled the system after installation but a new problem presented.
Now the air vents blow hot air (even when the dial is on 3 blue dots and at all fan settings). I scoured the internet for help and read that it could be the Heater Control Valve. Most people had problems with it failing and experienced no heat in the HVAC system but I was wondering if it could fail and lead to too much heat being delivered to the cabin? Any ideas?
Hi
It sound's like the heater valve unit has stuck in a open position or is not getting signals to operate correctly, check out power to the unit via fuses etc, if ok strip out the valve unit and look for any degrading of the rubber seals and or sticking mechanisms.
Hope this might help.
Is it that it's blowing hot air or is the air just not cold (like the A/C isn't working)?
I've just started having the same issue with my '95 318i. Hot air coming in all vents no matter the dial settings (rotary knobs) for temps(left and right) or which vent selected. I'm tending to agree with 740iss about the heater valve unit stuck open. I was also wondering if it could be the vent flaps are stuck open. ?
DID YOU 'burp' the cooling system? There is a big plastic screw atop....do you know?
Last edited by Eaglesail; 04-27-2017 at 07:20 PM.
Sensors in the BMW cooling system will send false and with negatives that can, and will cause issues that you describe.
Last edited by Eaglesail; 04-27-2017 at 07:25 PM.
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