The engine's coolant cools the cylinders and the head. The oil picks up the heat from the crankshaft bearings, and a bit from cam bearings, piston pin, etc., and some from the oil scraped down from the cylinder walls. Engines that have oil spray nozzles to cool the pistons will have that heat in the oil, also.
The oil is mainly cooled by air passing the oil pan. There is probably some transfer of heat from the oil through the metal to the coolant in the heads.
It is very common for oil to be hotter than coolant in hard operated engines, and for oil to be much cooler than coolant in lightly run engines in cool weather. There isn't a direct relationship between oil temperature and coolant temperature.
Ken
[ September 18, 2003, 11:37 AM: Message edited by: Ken2 ]