>> Granted adding glycol to water will increase the boiling point of the
mixture (H2O and glycol), but it will
also reduce the coefficient of heat transfer. In other words you won't
remove as much heat from the engine and engine temp will actually
increase not decrease.<<
All true. I'm no expert but I wonder if the thinking was to avoid pockets
of vapouor in the heads, which would also decrease heat transfer.
We saw 40 deg C drop in head temp when we went from 100 % glycol (as Rotax
suggested, we were only the second customer built Europa to fly) to 70 %.
912s have been known to boil after shutdown if not allowed to cool a little
while running. Not normally a problem except when doing extended ground
running.
Graham
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