Starting the motor to get the air out will not help, as the pump will not remove the air but distribute it all over.
You need to fit "Bleed" Valves at the highest points in the system.
You must use a good Antifreeze at the maximum mixing rate that the bottle recommends.
You must run the motor, then switch it off, allow to stand for a few minutes, then only bleed. Repeat this till no more air comes out.
Also remove the electrical thermostat, and look at the heat range, your fan may be coming on too late, fit a Fiat or such type in.
Also look at the Mechanical Thermostat in the block, this may be stuck, or too high value.
The best to do, is drill a 4mm hole into the thermostat, then the air will not get trapped behind it, and fail to open as the hot water can not reach the thing to open it.
This is an old trick I learned at the race track with hotted up motors...
DID you fit an header tank, and non opening radiator cap???, as the blow off must be via the header tank.
Hope this helps....
Herman
