Increased Coolant Flow, Decreased Coolant Temperatures The rear cylinders on the 5.9/6.7L Cummins suffer from a lack of coolant flow, and therefore, experience the highest coolant temperatures. This can cause excessive pressure to build in the cooling system, especially the rear of the block and blow out freeze plugs externally, or the smaller diameter plugs under the valve cover, leading to a failure. Our coolant bypass kit adds a secondary thermostat, that unlike other brands, 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. Benefits: Lowers coolant temperature at the rear cylinders Ensures consistent temperatures across all cylinders Prevents damaging coolant pressure build up Complete kit comes with braided hose and AN O-ring fittings to ensure a leak-free installation. Kits for MY 2003+ include billet hose brackets. Why do I need a Fleece Coolant Bypass? One of the biggest issues on the 5.9/6.7L Cummins is the coolant flow problem to the rear cylinders. This can cause catastrophic failure or blow outs of the freeze plugs in an over-temperature / over-pressure condition. The Fleece Coolant Bypass is one of the most important additions you make to improve the reliability and longevity of the Cummins platform. The '03-'07 5.9L automatic transmission version will eliminate the factory transmission fluid heat exchanger. The heat exchanger is not a fluid cooler, it was designed for use in cold climates to warm the transmission fluid with the engine coolant. It is not necessary for use in warm climates or high horsepower applications, nor does it detrimentally affect the trucks performance when removed. All 07-13 6.7 trucks, both automatic and manual equipped transmissions, do not have a transmission fluid heat exchanger.
Recommended Cross Sell Skus - FPE-DPK-59-0307/FPE-351-0407
Complete kit comes with braided hose and AN O-ring fittings to ensure a leak-free installation
Ensures consistent temperatures across all cylinders
Lowers coolant temperature at the rear cylinders
Prevents damaging coolant pressure build up
The Fleece Performance coolant bypass kit is designed to address critical coolant flow issues in the 5.9L/6.7L Cummins engines found in Dodge Ram trucks from 2004.5 to 2007. These engines are prone to inadequate coolant circulation to the rear cylinders, leading to elevated coolant temperatures and potential engine failure. Our kit introduces a secondary thermostat that operates based on temperature rather than pressure, effectively reducing coolant temperatures at the rear cylinders and ensuring uniform temperature distribution across all cylinders. This feature helps prevent excessive pressure buildup that can cause blowouts of freeze plugs or other costly damages, significantly enhancing engine reliability and longevity. The kit includes high-quality braided hose and AN O-ring fittings for a secure, leak-proof installation. For models from 2003 onward, billet hose brackets are included, simplifying installation and providing added durability. The Fleece coolant bypass not only improves cooling efficiency but also eliminates the factory transmission fluid heat exchanger in 2003-2007 automatic transmission models, which was originally designed for cold climates and is unnecessary for warm environments or high-horsepower applications. Removing this heat exchanger reduces unnecessary stress on the cooling system without affecting overall truck performance. This upgrade is essential for owners seeking to prevent catastrophic engine failures caused by coolant pressure issues, especially in demanding driving conditions or high-performance setups. Suitable for both manual and automatic transmission trucks, the kit is a vital addition for maintaining optimal engine health and performance in Dodge Ram 2500 and 3500 models during extended use.
Features:
Improves coolant flow to rear cylinders, reducing high-temperature hotspots
Operates based on temperature to prevent pressure buildup and leaks
Includes braided hose and AN O-ring fittings for a leak-free installation
Eliminates factory transmission fluid heat exchanger in applicable models
Ensures consistent engine temperatures across all cylinders, enhancing durability
