DIYbanter - View Single Post - OT

wrote:
John Scheldroup wrote:

Really cold weather and your engine can overheat from lack of water.
Really hot weather and your engine can overheat from lack of water.

Water conducts heat, does ethylene glycol ?,

Of course it does.

In a liquid cooled system convective heat transfer is far more
important than conduction, especially within the liquid itself.

Good convective cooling relies on turbulent flow. The heated
fluid near the surface being cooled is transported by the
turbulence out into the mainstream. That heated fluid mixed
out into the mainstream is replaced by cooler fluid and so
on. Turbulent flow is created by fast flow rates and narrow
passages. The fast flow rate also carries the heated fluid
faster to the radiator (actually a 'convector') transporting
heat out of the engine.

A high flow rate can mitigate the reduced effectiveness of a
coolant with a lower heat capacity, but engines, and therefor
the flowrates for their coolants are designed for a 50/50 water
ethylene glycol mixture. If you want to run on pure ethylene
glycol you need to pump the coolant faster through the engine.

Also, IIRC (please check) pure ethylene glycol has a lower
boiling and a higher freezing point than a 50/50 mix of
ethylene glycol and water. Adding water to the ethylene
glycol raises ehtylene glycols's boiling point and lowers
its freezing point too.

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FF