Cummins Coolant Bypass Kit

Features:

• Reduces rear cylinder coolant temperatures
• Improves cooling balance across all cylinders
• Prevents freeze plug blowouts
• Thermostat-controlled bypass activation
• Includes braided hose with heat protection
• AN O-ring fittings for leak-free sealing
• OE-style fit for clean installation
• Ideal for towing or performance builds
• Compatible with factory EGR systems
• Helps prevent hot spots under heavy loads
• Backed by Fleece Performance engineering

Keep Your Cool When The Heat Is On

When you’re hauling heavy loads or pushing your 6.7L Cummins hard, keeping temperatures under control isn’t just a matter of comfort, it’s about protecting your investment. The Fleece Coolant Bypass Kit gives your engine the extra cooling support it needs where it matters most, at the rear cylinders. These areas tend to run hotter and see more stress than the front, which can lead to pressure spikes and blown freeze plugs over time. Fleece solves that issue by adding a thermostat-controlled bypass system that kicks in when temperatures climb, ensuring smooth, consistent coolant flow through all six cylinders. Whether you’re towing through the mountains or tuning for more horsepower, this kit helps your truck stay steady and reliable under pressure. With premium braided lines, leak-free AN O-ring fittings, and an OE-style fit, it’s a clean, durable upgrade that installs with confidence and delivers peace of mind every time you turn the key.

Engineered For Balanced Cooling And Lasting Performance

The Fleece FPE-CLNTBYPS-CUMMINS-1318 Coolant Bypass Kit isn’t just another cooling add-on, it’s a precision-engineered solution to a known weakness in the 6.7L Cummins cooling system. Factory setups often leave the rear cylinders running hotter than the rest, leading to uneven temperature distribution and long-term reliability issues. Fleece’s system uses a secondary thermostat to regulate flow based on temperature rather than pressure, allowing coolant to circulate evenly across all cylinders. This design reduces hot spots, stabilizes coolant pressures, and helps prevent freeze plug failures that can lead to costly repairs. The kit comes complete with high-quality hardware, including a braided nylon hose with a high-temp protective sleeve and durable AN O-ring fittings for a perfect seal. It’s also compatible with factory and modified EGR systems, making it a versatile choice for both stock and performance-driven trucks. Built for those who demand more from their Cummins, this kit ensures efficient cooling under the toughest operating conditions.

Fitment: 2013, 2014, 2015, 2016, 2017, 2018 RAM 2500/3500 6.7L Cummins

Notes:

• Designed for 2013-2018 RAM 2500 and 3500 6.7L Cummins engines
• Addresses rear-cylinder overheating common in Cummins engines
• Temperature-activated bypass performs better than pressure-only designs
• Reduces risk of freeze plug blowouts and hot spots
• Ideal for high-performance, heavy-towing, or extended-idling applications
• Compatible with factory and modified EGR systems
• Not compatible with deleted EGR setups without a crossover pipe
• Includes AN O-ring fittings for a leak-free seal
• Comes with front and rear thermostat housings for complete integration
• Features braided nylon hose with high-temp protective sleeve
• Provides OE-style fitment for a clean and easy install
• Backed by manufacturer’s limited warranty