Hello Anthony, if it has oil in the coolant & not water in the oil it has to be coming from a pressurised oil way. If it's the head gasket, check around the oil way to the head. Oil cooler's are prone as I'm sure you're aware, water pump will only leak coolant into sump. Other places to check would be cracked head, block or water cooled turbo if it has one. Hope this is of some help, Alan.