Heater blowing hot/Cold when set on heat?

[DannyCop]

Just bought a 98 Z3, when set on highest heat, it will blow hot for a short period then cool air. Is this a thermostat sticking?

Anything else I should be aware of with this model? Manual Transmission.

Thanks
Danny

[dcs]

I have a similar problem with my 98 Z3. When car is moving forward or racing engine, heat works when sitting still and engine just idling, it is cool. Anyone know what is going on??

[DannyCop]

I can tell you what my problem was. I apparently had an air bubble in the radiator. With engine running and heater on and blowing high, I topped off the radiator and this cured my problem. Hope this helps.

Originally Posted by dcs

I have a similar problem with my 98 Z3. When car is moving forward or racing engine, heat works when sitting still and engine just idling, it is cool. Anyone know what is going on??