Head Removal Not Required For Installation
Temperature Activated Secondary Thermostat
Ensures Consistent Coolant Temperature Across All Cylinders
Available with Braided Black Nylon or Braided Stainless Steel Hose
1 Year Limited Warranty
Note: For trucks equipped with automatic transmissions only.


Keep consistent coolant temperature to all 6 cylinders in your 2003-2005 Dodge 5.9L Cummins with an automatic transmission by installing a Fleece FPE-CLNTBYPS-CUMMIINS-0305 Coolant Bypass Kit. The factory cooling system handles the job of keeping a stock engine running at optimal temperature. Once performance modifications are introduce, the additional heat generated by turbo, fuel, and tuning upgrades can quickly overwhelm the cooling system. The rear cylinders begin to suffer from a lack of coolant flow, experiencing higher coolant temperatures and the buildup of excessive pressure in the cooling system. This can cause the freeze plugs to blow out or the smaller diameter plugs under the valve cover to fail.

Fleece’s Coolant Bypass Kit utilizes a secondary thermostat which operates based on temperature instead of pressure, ensuring consistent temperatures across all six cylinders. This solves the factory issue of poor coolant flow to the rear cylinders before it ever becomes a problem. The complete kit includes high quality O-ring fittings and AN hose connections with your choice of braided stainless steel or braided black nylon hose for a secure, leak-free installation.


Additional information

Weight 15 lbs
Dimensions 4 × 9 × 12 in


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