Hi I have a 2006 f350 with the 6.0. the motor is stock. Yesterday I drove the truck for about and hour and romped on it pretty good coming up the hill to the house and then this morning I came out and there was a good size puddle of coolant on the ground. Any ideas what to check first.

 

Radiator cap

 

Also, make sure you are not over filling the bottle. If it's much higher than the bottom mark it's too much. The markings on the bottle are wrong and misleading.