2003-2007 CUMMINS COOLANT BYPASS KIT

Coolant Bypass Kit | 2003–2007 Dodge/Ram Cummins 5.9L

Protect your 5.9L Cummins from premature injector cup and cylinder head failures with the Fleece Performance Coolant Bypass Kit. Designed for 2003–2007 Dodge/Ram 2500/3500 trucks, this kit reroutes coolant flow to eliminate the factory design flaw that allows hot, stagnant coolant to sit around the injector cups — one of the leading causes of cup erosion, coolant contamination, and catastrophic head damage on the 5.9L common rail Cummins.

Why You Need a Coolant Bypass Kit

The 2003–2007 5.9L Cummins has a known issue where coolant flow through the cylinder head becomes restricted and stagnant around the injector cups. This localized overheating accelerates injector cup erosion, allowing coolant to enter the combustion chamber and fuel system. Left unaddressed, it leads to white smoke, hydrolocking, and expensive head repairs. The Fleece coolant bypass kit keeps coolant moving, reducing heat soak and dramatically extending the life of your injector cups and head gasket.

Features

• Eliminates stagnant coolant flow around injector cups
• Reduces localized overheating in the cylinder head
• Extends injector cup and cylinder head life
• Helps prevent coolant contamination of the fuel system
• Complete kit with all necessary hardware for installation
• From Fleece Performance — a trusted name in Cummins performance and reliability

Fitment

• 2003–2004 Dodge Ram 2500/3500 Cummins 5.9L CR
• 2004.5–2007 Dodge Ram 2500/3500 Cummins 5.9L CR

This is one of the best preventive maintenance upgrades you can do on a 5.9L common rail Cummins. Don't wait for injector cup failure — install the bypass kit and keep your engine protected.