Got the car back from the mechanic, 20 miles into it back home the car starts heating up. Got around 240 then I pulled over to turn the car off, and the Radiator overspill unit was spraying coolant and steam. After inspection, and a chemical block check the head gasket wasn't blown. We noticed that the electric fan is having intermittant problems (sometimes working sometimes not) so we think that is the culprit. It was wired by the previous owner to work all the time instead of only working at certain temperatures. The place where the fan is tapped into is getting a strong 12 volts. So I guess my question is, would the fan not working be the cause of all this? He's also thinking it may be a stuck thermostat. Please advise, thanks in advance.