Overheating on 2016 A. Interstate Sprinter

[Sailmiami]

Our 2016 AI Sprinter has started somewhat overheating recently. It's worst when going up hills at slow speeds, it seams to do better at highway speeds. So I think it may be an airflow problem. The radiator appears unobstructed and cooling fluid appears good. The radiator fan offers some resistance when turned by hand.It has 60 thousand miles and all service has been performed by Mercedes. When it's 70 degrees outside it takes the engine about 15 Minuts to worm up to 150. It has never gone in to the limp mode, but it's defenetly running hotter then it used to. Has anyone incountered this? Any suggestions are welcome.

[rowiebowie]

I have no diesel experience, but if my gas engine was doing that, I'd suspect the thermostat. Maybe stuck partially open preventing warm-up, and yet not opening fully to provide needed cooling.

[Titus]

Do you hear the fan running when it gets hot. Having a problem at slow speeds suggests the fan. At higher speed you should get most of the airflow due to vehicle speed, not the fan. I don't think that a thermostat problem would be vehicle-speed dependent.

I have never timed how long it takes mine to get to 150. I do know that on real hot days going uphill with the AC on the engine temperature was far higher than normal. I turned off the AC and the temperature drop was amazing. Not so much a reduction in engine load but rather no heat load from the AC heat exchanger that is in front of the engine coolant heat exchanger.