Fleece Performance FPE-CLNTBYPS-CUMMINS-12V-SS Coolant Bypass Kit 1994-1998 Cummins 12V 5.9L Stainless Braided

The Fleece Performance Coolant Bypass Kit solves a critical cooling system flaw in 1994-1998 Cummins 12V 5.9L engines. The rear cylinders suffer from restricted coolant flow, causing dangerously high temperatures and pressure buildup that can blow out freeze plugs externally or small plugs under the valve cover, leading to catastrophic engine failure.

This complete kit adds a secondary thermostat that operates based on temperature—not excessive pressure like competing designs. By proactively managing coolant flow before pressure becomes critical, it ensures consistent temperatures across all six cylinders and prevents damaging pressure spikes.

Key Benefits:

• Lowers coolant temperature at rear cylinders where heat buildup is most severe
• Maintains uniform temperatures across all six cylinders
• Prevents freeze plug blowouts caused by over-temperature and over-pressure conditions
• Temperature-activated secondary thermostat (not pressure-activated)
• Improves engine reliability and longevity on the Cummins platform

What's Included:

• Secondary thermostat assembly
• Stainless steel braided coolant lines for durability
• AN O-ring fittings for leak-free installation
• All necessary hardware for complete installation

Application: Designed specifically for 1994-1998 Dodge Ram trucks with 5.9L 12-valve Cummins engines (VP44 and P7100 injection pump equipped). This is considered one of the most important reliability upgrades for the 12V Cummins platform.