Fleece Performance Cummins Coolant Bypass Kit with Stainless Steel Braided Line (2003-2007 Manual Transmission)

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. 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. Cummins Coolant Bypass Kit (2003-2007 Manual Transmission) w/ Stainless Steel Braided Line

• 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 Cummins Coolant Bypass Kit (Part Number: FPE-CLNTBYPS-CUMMINS-MAN-SS) is designed to enhance the cooling system of 5.9L and 6.7L Cummins engines from 2003 to 2007 with manual transmissions. This comprehensive kit features a secondary thermostat that operates based on temperature, unlike traditional pressure-based systems, providing precise control over coolant flow. By maintaining consistent temperatures across all cylinders, especially the rear ones prone to overheating, this kit helps prevent excessive pressure buildup that can cause freeze plug failures or engine damage. The installation includes durable braided stainless steel hose and AN O-ring fittings, ensuring a leak-free connection and long-term reliability. Proper coolant flow is critical for engine longevity, and this bypass kit addresses common issues associated with uneven cooling, reducing the risk of catastrophic failures under high-temperature conditions. Its design improves overall engine reliability, making it a vital upgrade for Cummins owners seeking to optimize engine performance and durability.

Features:

• Complete kit includes braided stainless steel hose and AN O-ring fittings for a secure, leak-free installation

• Ensures consistent coolant temperatures across all cylinders, especially at the rear

• Reduces coolant temperature at the rear cylinders to prevent overheating

• Prevents damaging coolant pressure buildup that can lead to freeze plug blowouts

• Designed specifically for 2003-2007 Cummins engines with manual transmissions

Air Freight Prohibited: false
Not Carb Approved: false
Ltl Freight Required: false
Prop 65: Y
Part Type: automotive
Epa: Compliant
Carb Acknowledgement Required: false
Carb Eo Number: D-834-9
Regular Stock: t
Units Per Sku: 1