Richardt is right on, especially listen. It will have a popping sound that is very obvious.
Ford and Chevy both have this problem, it is more the design of the body covering the engine than the acutal engine, there isn't the airflow that they need. If you are running it hard (nearly any time considering the weight) let it idle to cool down for 3-5 minutes before shutting it off. I usually take a slow walk around, check the tires, toad hookup, etc. while it cools. If just a quick 10 minute break at a rest area, checking in at the campground, etc., I don't even shut it off.