Well I get out to one or two road course events each year. There are guys that attend with me who have oil temp sensors with the same vehicle. And they tell me that their oil temps can get pretty high at times during the event. We run a 2 mile closed road course (Gingerman Raceway in South Haven Michigan), we do 15 minute heats running full tilt the whole time. The track has eleven corners, three long straights, high rpms used a lot. I was wondering in theory if a certain weight oil would help better in terms of cooling properties. Would a thinner oil such as 10w-30 provide better cooling than a thicker oil such as 15w-50 because it circulates quicker, or does a thicker oil provide better cooling because it coats the internal parts better. My two choices would be 10w-30 or 15w-50. I have no idea which one would create less friction. My car is a Honda Civic, no oil cooler, stock cooling system, etc..... . Any info would be appreciated. Thanks.