bmwe21.net forums

Most will laugh reading this, but I recently discover that I do not use the heating system properly? Last weeks we have a fairly cold winter (for what we are used to here in Athens) and I am revisiting and rediscovering my e21's heating system
So I would like to ask a question: when you need to heat up the interior, what are you exactly doing? -pre facelift dash
I am guessing : 1) close the exterior fresh air vents (by pulling all the way down the two levers that are edge left and edge right) and 2) turn up the mid-left lever which controls the temperature ( red -blue, to the red of course). Then, 3) select direction of heating from the mid right lever (up to the windshield, or down to the feet etc)
My question is about number 4: do you use the Ventilation switch (the one that was called in German dashes "Lüfter" and selects the speed of ventilation)??
When the temperature is really cold outside,and the car is running, the use of this does not help the heat, after a while the air from the vents becomes cold
And if I turn off this one, after a while the heater works again
Is it wrong to use this when hot air is needed? Or is there something going wrong with my heating system?

Ehm, I think i should just propel more heated air in to the car. If not, I think something is wrong.

Thanks for reply mate
But what may be going wrong with the heater?
We have washed the cooler twice, changed the cooling fluid, have a new fan-electric one ...
Could it be that the fan cools down water more than the factory one?

​Last evening drove the car and focused a little bit on this
So the exact problem is :
Prop speed at 1/air direction towards feet/external air vents closed : hot air coming in, mainly from driver's(left side) foot vent
Right side foot vent bringing in some hot air mixed with cold!
If I turn prop speed to 2 or 3, the air starts cooling down and in some minutes I get cold air from both feet vents

I haven't yet checked what happens with the upper (defrost) vents, I have to check this

In any case I believe I need to take the car to a good electrician??

Sound tot me like a clogged heater element.
When you select higher blower settings the air flowing in the car gets cold again, right?


The heater element warms up with hot coolant from the engine. When the flow of hot coolant through the heater element isn't sufficient, the air blown through the heater element isn't warming up anymore.

The engine temperature is ok?

Check following:
Clogged heater element (for coolant)
Heater valve does not open far enough.
Clogged coolant hoses from engine tot heater element.

Thanks mate, this explanation sounds very logical, so we definitely need to look into the matter
Are all these elements easy to access or will any of these require to remove the dash ?

PS in case it is heater problem, is it reparable in general, or should I find a new part?