I purchased a new 2006 dp in July, 2009. It has a cummins 400 ISL eng. with side radiator.I had a coolant temp alarm go off going up the moutain on I40 between Old Fort and Black Mountain NC headed west. It was at the top and the alarm went off within probably 10-15 sec. I thought the transmission would downshift as needed.My temp runs 200 deg on flat with or w/0 toad. Is this to high? Does anyone else run this temp between 62 and 65 mph? Do I need to manually down shift into 5th or 4th gear when approaching a grade? I read on another (Cummins) site you should keep the rpm up.
My BIL has a 2007 Monaca with the 400 ISL cummins with rear radiator and his temp runs a good 20 deg. lower than mine. I've read where this is a FL design problem ( not a large enought fin area on the radiator, needs to be larger) to you need to keep the rpm up. Would a lower temp thermastat help?
Anyone here have this experience and or solution without breaking the bank?
Thanks
Gary
My BIL has a 2007 Monaca with the 400 ISL cummins with rear radiator and his temp runs a good 20 deg. lower than mine. I've read where this is a FL design problem ( not a large enought fin area on the radiator, needs to be larger) to you need to keep the rpm up. Would a lower temp thermastat help?
Anyone here have this experience and or solution without breaking the bank?
Thanks
Gary