Cummins Coolant Bypass Kit

Features

• Lowers coolant temperature at rear cylinders

• Ensures even coolant distribution across all six cylinders

• Prevents freeze plug blowouts from over-pressure

• Patent-pending, temperature-activated design

• OE-style fit and finish

• Leak-free braided hose with AN O-ring fittings

• Complete, ready-to-install kit

Performance Benefits

The 6.7L Cummins engine in 2019–2024 RAM 2500/3500 trucks suffers from insufficient coolant flow to the rear cylinders, which creates higher localized temperatures and dangerous pressure build-up. This can lead to catastrophic failures like external freeze plug blowouts or internal plug damage beneath the valve cover.

Fleece’s patent-pending coolant bypass solution tackles the issue at the source. Unlike other systems that activate under high pressure, this system uses a temperature-controlled secondary thermostat to proactively redirect coolant flow, ensuring balanced temperatures across all cylinders—before high pressure becomes a problem.

This upgrade significantly improves engine reliability and is one of the most essential cooling modifications for long-term Cummins performance.

Kit Includes

• Rear coolant bypass thermostat housing

• Front coolant bypass thermostat housing

• Black braided nylon coolant bypass hose with AN O-ring fittings

• New EGR crossover tube gaskets

• All necessary mounting hardware

Fitment:

2019, 2020, 2021, 2022, 2023, 2024 RAM 2500/3500 6.7L Cummins

Warranty:

Manufacturer’s limited warranty

Fitment Notes:

For use on 2019+ RAM HD trucks equipped with the 6.7L Cummins. Ideal for trucks with high towing demands, performance upgrades, or reliability-focused builds.