Engine Temperature Gauge Reading

Posted by Packard 1948 On 2015/9/3 19:58:45

Where does your engine temperature gauge indicate when the engine is definitely warmed up on a warm day?

On this engine I have installed a 6 blade radiator fan, the system is pressurized with the radiator cap, and I also have installed a overflow bottle and I know that the water diffuser tube is solid and installed correctly and the radiator is clean, and I used a 150 degree thermostat.
(all this being said to demonstrate that the cooling system is in a known serviceable condition).


It seems that after a drive in relatively hot air 90 degrees F that the temperature gauge reads at approximately the 80% of its scale near the H position.

I ran an infrared thermometer on the thermostat neck and it was showing about 210 degrees. The head was significantly harder as would be expected. Next time I have it on the lift I will check the lower radiator output temperature with the engine warmed up.

The gauge does seem to stay about the same range even when cruising down the highway at 60 miles per hour.

Was the 150 degree thermostat a good idea? What is the stock thermostat temperature set for?