A good friend has a (lets say a truck). Not really but this is a general natured question. It runs hot while driving but will sit for an hour and run cool as can be. It has a standard fan and an electric fan that cuts on with the ac compressor. I told him to make sure his guys didn't put the regular fan on backwards. I figured that would fight the flow of air when you are moving but cool just fine stopped. Does anyone have any other suggestions. It has a manual transmission, a fresh rebuild on the motor and trans, new radiator core and hoses. Thew added the ac and it was running while the (truck) was sitting running in the shop.

Thanks for any hellp
Neil