Weekend 1.6 twin cam. I get lots of air in the water, it bubbles into the header tank. seems to start when the thermo opens. Hope it's not the head gasket, the engine runs ok, no steam from the exhaust. Where else do I look?

Have the cooling system presurized at a good workshop.

Thanks Peter. The car had a little oops with a tree and the radiator had to be replaced with other bits and pieces. Pressurizing is new to me, I thought that bleed screw would let all the air out. Anyway, will try a bit of force feed and hope the situation improves. Like you, the Fiat must go, but for different reasons.