I am considering replacing my radiator (30 Tudor built in Berlin). Mine spits water through the cap when under load at low RPM (lugging)....like when in 3rd gear and the hill gets too steep and down-shifting requires slowing down too much to be practical. I have had all kinds of input from the Barn...leaking head gasket...replaced it...exhaust manifold gasket leak...replaced them...water level to high...let it get low...it still happened...cooling system blocked with too much corrosion or sediment...flushed twice...water flowed clear wit no debris. Can it be the water pump? Is there some sort of block inside the radiator that causes it? The engine runs pretty cool...even after about a 25 mile run in warm weather (German summer...about 90F) the engine is not particularly hot to the touch and no steam at the radiator. I am running out of logical options. Any ideas?