BMW e46 Heater control valve check and diagnostic

[@milivojmilosevic1172]

Thank you so much for this video ! I found your video while searching for a solution to my problem. My 2005 e46 325i does not blow warm air thru vents, only cold air.

[@TheOnlyRaceEngineer]

great explanation. SUBSCRIBED

[@liambrindley9087]

The reason is that the valve is to help the passengers stay warmer even when the engine has stopped, its more of a comfort thing, i noticed when mine wasnt working properly as the cab heating instantly goes cold after shut off 👍🏼

[@kosteg83]

no, it's opposit. it's to avoid overheating of cabin when engine will be started again within 15min and heatcore will be filled with hot water from engine.

[@PauloFerreira-jq1nz]

The Valve stays on in the initial 15minutes to allow the motor get warmer faster, if the valve opens straight away the motor will have to cool all the water in the heating element thus extending the warming up time. A little bit as a temperature valve only that with a timer.

[@rick23ro]

My new valve keeps getting stuck after driving more than 30 mins. I got the cap off and jiggled the piston to release it and had it working again for my next ride, but got stuck again. I noticed that after reaching almost the temperature set on the auto AC unit, the valve starts to knock regularly, meaning that it closes, then opens after 2 seconds, then closes again after another 2 seconds and so. I noticed this while standing still and confirmed by holding my hand on the hoses that enter the valve. After doing this repetitive open/close actions, the valve eventually gets stuck somehow. It's a Febi valve mounted few months ago during the summer. Not sure if I should buy a new valve or if this continuous opening/closing at 2 seconds is in fact the problem and I need to replace the AC control unit and not the valve...

[@Sp3NgL3R_MF]

Can you please tell me what is the part numbers for hoses that are connected to it ?

[@Ndzila-pl6qw]

great video...does this heater control valve also responsible for cold air? .... from Mzansi.

[@DIYTEA]

@@Ndzila-pl6qw No. Cold air will flow through the evaporator and this valve should be closed.

[@kosteg83]

According to technical data this 15min valve off is to avoid overheating of the passanger compartment for short stops. If you are going to fill up tank, engine off - when valve will be open heatcore will fill up with hot water and just after starting car again you will have a hot air blow. So, to avoid it, valve stays close to prevent of mixing water from heatvcore with engine water. In e46 there is no "rest" button on heating panel. There is no single function to control cabin tempereature when engine is off. And to be honest - e9x, e6x, or even e39 - with "rest"button - all of them to allow of adjusting cabin temperature when engine is off - they are using additional electric water pump and stays valve open/closed depends of needs.

[@DIYTEA]

Sounds very logic to me, thank you for sharing. In addition to the confort may be to protect the heating components from overheating.

[@wonderwalls3565]

why would the compartment get hot air? The air will not go from heater core into the blower motor because the flap which switches the flow from hot to cold will be in the position to allow cold air only?

[@kosteg83]

​@@wonderwalls3565 there is no flap to control temp in e46. Such watervalve is the only part (together with electronic for Control) responsible for setting temperature on e46 passanger compartment. And as I wrote - if car is hot, when we are stoping for filling the tank or short shopping ect od valve wilk be open then heatcore will be hot. And just after starting car again hot air will blow from vents. This is the reason why valve od closed ca. 15min after engine off.

[@wonderwalls3565]

@@kosteg83 I did not mean flap for temperature. flap for diverting the incomign air. it the setting is on heat, the flap will open in such way that the air coming from the heater core enters the cabin but if the setting is on cold the flap closes the air coming in from heater core and allow air coming in from cold system. Is that not the case with E46?

[@kosteg83]

​@@wonderwalls3565heating/cooling system in e46 is simple as possibile. Incoming air travels always via a/c evaporator then via heat core. There is no single Flap beside this to open/close external air input. The only one exeption is the middle air vent with additional dial to change air temp just for them.