Have a 05 Fleetwood Expedition 38N, Cat C 7 engine & 6 sp Allison trans on Freightliner chassis, towing an 04 Jeep Unlimited. Had overheat warnings several times & mech in Tumcumcari, NM used a hot water pressure washer to clean radiator from both sides, solved problem instantly, He then installed a slobber tube extension USING AN OLD RADIATOR HOSE to within 6 inches of pavemnt, no more overheat problems in over 6000 miles. He says he has done the same thing many times on other brands of diesel pushers & has always worked well.
Wayne