Search the Community

Have 2007 Holiday Rambler Endeavor with 400 HP Cummins ISL with 88,000 miles, original owner. Started experiencing overheating issues on return trip from Pacific Northwest while outside temps were 103 to 105. Started seeing engine temps running in 220 range on even moderated grades but only at 224 did check engine light come on till cresting grade however in the 205 to 208 degree range i started experiencing engine derating or loss of power on grades. As I had filled up with biodiesel for first time on Washington State, thought may have fuel filter issue so had them changed in Utah. Problem persisted but i limpen back to WV and immediately went to local Cummins Engine Service Center. Diagnostic codes only showing overheating issue but had cooling system checked out and flushed, new fuel filters again, fan checked out, water pump and t'stat replaced, and a sensor that is tied into engine derating replaced. Derating problem continues. engine preforms great on level grades and generally temps do not get extreme until heavy grades. On even moderate grades the stop engine light is coming on at anywhere from 197 to 210 and a significant loss of power starts to occur on moderate grades. on one extreme grade i did have engine temps exceed 224 and Check engine light came on as temps went to 228 before cresting hill. pull the hill only maintaining 25 miles per hour. again limped home home ant took it to Cummins. they seem to be at a loss. I question EGR but their diagnosis seems to point to no issue. Anyone else experience similar issues or have thoughts to point me in a direction.