In the process of restoring a 1963 Thunderbird convertible and I need some help isolating an overheating problem at highway speed.
Status to date:
1-No apparent coolant leaks.
2-No heating issue at idle.
3-Heat sender seems to be operating fine.
4-New thermostat opens and pump is circulating the coolant.
5-Checked for head gasket leaks using block tester no combustion gases detected.
6-Radiator appears to be in good shape.
7- Radiator fan has excellent air movement.( There is no fan clutch)
8- No sign that water is getting in the oil.
9- Radiator hoses and belts recently installed.
Any ideas would be appreciated.