[335i101]

Not sure what my problem is...little to no heat in cabin. Lower radiator hose cool/cold, upper is hot/warm.

No smell of coolant or leaks on floor. So, I think it is thermostat. Can I just replace that without soon the waterpump......if so anyone know of DIY??

[rusty_g80]

I know this thread is old, but did you ever find out what the problem was?

[335i101]

Originally Posted by rusty_g80

I know this thread is old, but did you ever find out what the problem was?

Nope....luckily it summer so it is bothering me...until winters comes again....

[335i101]

Ok I have almost no heat in the car.... I made apt at BMW and they said it is probably a water valve and is easy to check/fix.....anyone know I can do it?!?

[Caruso0644]

I had the same problem with mine last year, they had to replace the whole radiator because of a faulty sensor that is installed in it.

[335i101]

Originally Posted by Caruso0644

I had the same problem with mine last year, they had to replace the whole radiator because of a faulty sensor that is installed in it.

Thanks for the words of encouragement....do you know the price of that??? I think anything is cheaper than replacing heater core...

[335i101]

Went to dealer today, they flashed the system and said I needed a 2k heater core....

[bmiller929]

I have a similar problem with my 335i, low heat. When the car is up to temp all hoses are hot (upper/lower radiator hoses and both hoses to the heater core).
The temp out of the vent gets to about 105 -110f (my 328 gets to 130f)
All the controls work so I hope that the heater core is not clogged. Could this be if both heater core hoses are hot?

[bmiller929]

I was able to flush out the core using compressed air then filling with water and continuing to use air to clear the lines. now the temp is 140!
I had to flush it about 10 times until the water was clean coming out.
I had to try it before coughing up $2k