BMW 328I No Heat ..Cold air only

Put some coolant water in it. We had the same problem, cold air when the car stopped, and warm when higer speed. Needs coolant water, at least that fixed our problem :)

I had this exact same problem on a 99 328i also. It would heat up when I drove fast, but when i was going slow or at a light I would only get cold air. Cooling worked fine. Finally took it to a mechanic. They replaced the water pump and the thermostat and the problem went away. Although personally, I saw the old water pump and it looked great. I think it was probably the new thermostat that did the trick. But i had both replaced and the problem definitely went away.

water pump may be the way to test take off cap when cald hold reves see if water flys out if so ok if not water pump maybe on the way out