Castor turns into different polymeric chains as temps rise, becoming more and more resistant to heat. Basically it turns in to a few different types of natural plastics which creating a layer over the surfaces and at the temps, it acts like a barrier lubricant. It also runs to heat, instead of away from it like almost all other oils. Hotter the temps get, better castor works. Down side is it leaves the coating, and needs to be cleaned off now and then, but with todays formulas, the cleaning part is reduced majorly.