The rear cylinders on the 6.7L Cummins suffer from a lack of coolant flow and because of this experience the highest coolant temperatures. This can cause excessive pressure to build in the cooling system, especially the rear of the block. This can blow out freeze plugs externally, or the smaller diameter plugs under the valve cover, leading to a failure. Fleece’s coolant bypass kit adds a secondary thermostat that works based on temperature instead of excessive pressure. This solves the problem before pressure becomes an issue by ensuring consistent temperatures across all six cylinders.
For 2007.5 – 2018 model year Dodge Ram 6.7L Cummins trucks, including both automatic and manual transmissions, factory installed transmission fluid heat exchangers are uncommon. For customers with a 6.7L that has a heat exchanger, a heater tube can be purchased at your local Chrysler Dealership (Part Number 68048997AA) to complete the installation.
