H3LZSN1P3R
You're doing it wrong
They may have thermostat issues or really low opening thermostats or the thermostats removed. With the thermostat closed the rad gets no flow the coolant just circulates in the block/ egr cooler and heater core linesI’ve never had a fan stick on a small Cummins, but have at work on my isx. Truck hovered around 165 and another cat we have if the manual switch is on it won’t even get hot enough to regen.