Cummins 400 ISL Overheating Problem

[windsorbill]

Originally Posted by JLAppel

I am extremely happy to report that in he 2 1/2 years since the original posting, the issue has been very simply (and inexpensively) resolved. I followed the suggestions of several contributors and purchased a gallon of approved antifreeze. Added coolant to the top of radiator (right up to the bottom of the cap. Problem has not reoccurred since. As I understand the situation, the low coolant sensor is located in such a position that when the front of the coach elevates (like going up a steep grade) the coolant level drops below the sensor level triggering the alarm and subsequent shutdown. Filling the radiator past the maximum level fill line allows the coolant to maintain a level above the sensor. Before going to any great mechanical expense, I suggest this remedy - it has worked for me. As stated earlier, I have not had a single repeat occurrence in over 2 1/2 years.

Thanks for posting your solution. Very handy info to know if it every happens to me or others.

[timjet]

I'm new to this so be gentle. So the engine never overheated, the low coolant sensor triggered an overheat warning. Wouldn't a fault code be generated to tell you this. Shame on Cummins for putting you through this by connecting the low coolant sensor to the overheat warning.

[pmpurcell]

Good info; Thanks. I have the same problem in my '08 Tuscany with the Cummins ISC 360. It happens coming off the highway to a traffic light. The temp runs within normal limits at highway speeds and then overheats at slower speeds like passing through a small town. The "high coolant temp" warning triggers, but last week was the first time it shut down the engine. It can idle all day long at normal temperature.

No coolant leaks. Water pump operates normally.

Stay tuned while I work this up. I believe that the fan controller is not switching the fan to full speed.