Would a craked reservoir cap cause your car to run hot it is leaking from the cap?

A Cracked reservoir Cap would in most cases cause your car to over heat. After your car has ran a while, and built up pressure it would begin to loose water in the form of steam. Once your car is parked and shut off it will then begin to loose water. Once parked your car looses compression which causes the water to boil instead of steam. You would then loose water at a faster rate emptying your radiator and causing your car to run hot.