Hi
Nearly everyone has airlock issues with subi motors. Im not up to that stage yet with my conversion but with my old wasserboxewr bug I just made sure that the fill point was extremely high, I used the wasserboxer header tank (recovery type system) with an overflow bottle, I could fill my motor when it was cold and the recovery system would get rid of any bubbles in the header tank, the motor needed to heat up, expell air into the recovery system and then draw back coolant in its place, I also had a tiny hole drilled in the thermostat to allow the cold coolant to equalise on both sides of the thermostat.
Steve
My setup before the turbo,
