[zoner]

Is the arrow (embossed on the outward side of the thermostat) pointing straight up to the sky? This is critical.

There is only one fan on 318ti's- when the A/C is turned on, the fan runs constantly while the ignition is turned on. When A/C is turned off, the fan is controlled by the thermo switch in the radiator.

Are you bleeding the air out of the system correctly? Sometimes it takes several attempts to get it right and get all of the air out.

I'm out of ideas for the night...