Engine Temperature

[Stevenblanca]

Originally Posted by SR1355

I run hot when on trail... I've noticed it seems to be a combination of fan CFM and water pump rate. If I sit at idle in 100 weather the gauge will creep upwards toward the red zone... If I run the engine at around 2K rpm, in neutral, the temp comes down. Does the fan run faster at higher RPM??? or is it constant RPM??? I know the water pump runs faster pushing more coolant thru radiator... It's never overheated but you can tell that it's damn hot. Wonder if higher CFM electric fan on other side of radiator would help...

The fan does run faster at higher RPM, it is driven by the engine. Water is the best medium to transfer heat. Coolant is not. You can check this with any cooling system expert if you don't believe me. Coolant just raises boiling point, lowers freezing point, prevent deposits, prevents rust. It does not cool or transfer heat better than water and it does not make water transfer heat better.

Specific heat of water is 1.0. Meaning it takes 1 BTU to raise 1 pound of water 1° F and is assigned the 1.0 specific heat number.

50/50 mix of ethylene glycol (green coolant) has a pecific heat number of 0.5
50/50 mix of propylene glycol (red stuff) has a pecific heat number of 0.3

Pure water will remove double the amount of heat and carry that heat away from the source per unit volume compared to the 50/50 mix of the green stuff.