Normally i find, when it can idle away and be fine, but once driving(higher speeds highway etcetc) and it starts to cook, its a flow issue (eg pump or radiator)
A cooling system should be under pressure, it will constantly cook if its never pressurizing, raises boiling temp once under pressure
when its pissing water out the overflow is it boiling??? or does the overflow jsut keep over filling??? cooked my first 4a because rad cap didnt seal and as soon as it got hot it didnt hold pressure it would jsut dump coolant into overflow(wouldnt boil) until one night there wasent any more water to dump![]()