Though the 6.7-liter Cummins inline-six is overall reliable, problems with its cooling system can arise.
It’s not uncommon for the 6.7 Cummins water pump to start leaking over time. The water pump’s bearing can fail, and the plastic seven-blade impeller can break away from the shaft. In addition, a failing thermostat can lead to either overheating or no heat produced. +Read more
The thermostat may cease to open up and allow coolant from entering the engine, resulting in the engine overheating. The opposite can happen when the thermostat is stuck open, permitting coolant to continuously cycle through the engine and not allowing heat to build up.
ProSource Diesel offers everything you need to replace your 6.7 Cummins thermostat, water pump, and more.