My EF has experienced high engine temperatures about 6-7 times (not to the point of overheating, but close).
After changing thermostat, cap, water pump and checking the fan, it was due to a partially clogged radiator. The rad was serviced and everything seemed to return to normal.

However, after that service, when I push the engine to high revs, the temp shot up again. This happened about 6 times.
During normal driving, all was fine. Very slow loss of coolant but no obvious leaks. Experienced power loss.

Opened cap, reved engine and saw bubbles popping out from rad mouth. Compression slightly in cylinder No2.
Mechanic confirmed that head gasket has been damaged during the numerous and prolonged overheating occurences.
Maybe the cylinder head has also warped.

Last week, I changed the gasket, skimmed the cylinder head, flushed the engine block+cooling system.
Now, all cylinders have equal pressure, no more loss of coolant even after hard driving, and temp has remained rock steady.

So if anyone is experiencing my problems, pls save your time and go straight to the head gasket. Thanks again guys!