We previously owned a 2003 Jayco 23rd Class C with a 8.1l Chevy Engine. Never overheated and we traveled in some pretty hot environments. The only time we had any difficulty was going out the West side of Death Valley and it was the transmission that got hot plus the floor, not the engine. Part of the problem was the climb and curves so you couldn't go very fast so there was not a lot of air moving to aid the transmission cooler or to keep air flow around the engine so the exhaust made the passengers side floor pretty warm.
I know one person who has a 454 engine in a Bounder Class A and his engine has always run hot. He has an electric fan on both the front and the back of the radiator. Currently has a problem with the exhaust studs. I believe that part of the problem is that the engine has run so hot.
If I had a Class A with sufficient room there would be a radiator the size of a swimming pool in there ;-). We don't have that luxury in a class C. Also wondered if an air scoop on the hood could improve cooling by flushing more hot air from the engine compartment?
The engine in our current Ford based Class C does not seem to overheat, but then we have not been in real hot places with it yet.
