Car looks to be in great shape. New paint, very minor surface rust , relatively new vinyl interior. Starts right up when warm and with a little coaxing when cold. When we test drove the car, the temp gauge stayed at 190 and radiator fan came on as usual. After getting the car home and taking it for a longer drive, the car starts to overheat. At fist we thought that the rad fan sensor had gone kaput, tested it in hot water and it worked fine, next was the thermostat, pulled that out and tested in a pan of hot water. It starts to open at about 180 deg (measured with an infrared thermometer). So we reinstalled that component. Radiator looks to be clean, at least from the few core holes you can see from the rad cap. Have burped the cooling system a couple of times, both at the coolant "T" and the flush tee at the top of the heater hose. The system seems to take quite a long time to come to temp at the bottom of the radiator, even though the thermostat opens as it should. Coolant will boil into the overflow tank, almost as if the system still has to be burped. If after overheating, you open the rad cap or coolant tee, the rad looks full and maybe need to add just an ounce or less at the tee. Yesterday, took the car for a short drive, temp stayed between 200 to 240, as we pulled back into the drive, the heater went totally cold. No heater core or valve leaks that we can find, and coolant was boiling in the overflow tank. When loosening the coolant tee, air escaped. I would hate to think that there is a head gasket leak. ( no coolant in the oil or the other way around)
Any thoughts here , number one son is quite bummed
R/
