Originally Posted By: Stelth
My understanding is that synthetic base oils are more efficient at heat transfer.
I don't believe that either. Synthetics and conventional oils are ALL hydrocarbon liquids. They've all got the same heat capacity, thermal conductivity, etc. down to at least a couple of decimal places. Any slight difference in how effective they are at transferring heat would be related to, say, some difference in surface affinity. Polar molecules like esters might improve heat transfer slightly, but again.... its a burp in a hurricane. So small of a difference that it would be all but impossible to actually measure.
Actually, I could equally well convince myself that polar molecules would HURT heat transfer because a layer would adhere to all the metals and act as an insulator.
I just don't think it matters AT ALL.