I'm picking nits and it doesn't affect your conclusion but you don't have to get to the boiling point of water for the water to evaporate. Granted, it will happen much faster and do a better job above boiling but lower temps will drive off water.

Eventually, yeah. Depending on the length of your commute. It'll take forever at 160 degrees.

The lubricity of the oil is also reduced at 160* or lower. That's worse than any condensation in the oil which will emulsify or evaporate eventually.

Word of the day, lubricity. Using that at work today.

Shouldn't a thermostat, whether its sandwich plate or in line, take away the need for a cooler cover?

I think about 10% still gets through which is why guys end up making block off plates in the winter.

:iagree: