I have a Cummings 400 isl engine in my 2006 Monaco Diplomat. It has a rear radiator. Just trying to get some responses on what your normal water temperature is while running on a normal flat grade and what it climbs to while pulling a long 6% grade. Mine runs around 180 degrees on a flat grade and the highest I've seen it on a long 6% grade is 201 degrees.
Tony & Maryjane along with Sunny (Basset Hound)
2006 Monaco Diplomat 38PST, ISL 400
Toad-2014 Ford F-150 W/Air Force One Toad Brake