I have seen a lot of wrong information about synthetic oil... But this is a Doozie.
Where have you came across this??
The thermal capacity of mineral oil and full synthetic are close, they are effectively equal... BUT the Thermal conductance is better with synthetics... synthetic oil has a BETTER rate of transfer of heat than mineral oils... With the relative low temperatures found in internal combustion engines the heat transfer Advantage of synthetics in normally not included in the statistics, but synthetic oils do have an advantage in Heat TRANSFER...
You can find the exact stats in The Yaws Handbook of Thermodynamic Properties of Hydrocarbons and Chemicals....
KennyV, I'm with you all the way on this one. We may differ on our brand of choice, but we do agree that synthetics are superior to conventional oils. There is a TON of misinformation and myth out there with regards to synthetic lubricants.