Sorry I'm asking a lot of questions but I need to be pointed in wrong direction fitted 2nd hand rad into my p38 ( I'm broke couldn't get a new one). Drover less the 2 miles and it overheated. I felt the radiator the top was red hot but the rest of the radiator was stone cold. And the heater was blowing cold. The range has no previous over heating issues only needed a rad cos the old one split. Could it be blocked rad or thermostat? Possible air block