Real quick question on your over heat with proper coolant level. Have you had you water pump replaced either by choice or under recall notice? When I've replaced water pumps under the recall, I have to bleed all air from the system in
the shop then go for a drive. Which includes both city and highway driving. By the time I complete the 40 mile trip and return to the shop, I have to top off the coolant and clear codes for low coolant level.