Fleece Performance Coolant Bypass Kit - 98.5-02 Dodge Cummins VP


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Product Details

Product Name: Fleece Performance Coolant Bypass Kit - 1998.5-2002 Dodge Cummins VP
Manufacturer: Fleece
Thoroughbred Diesel Part #: FPEDG9812VPCOOLANTBYPASSKIT
Fitment Notes: 1998.5-2002 Dodge Cummins VP

Available in
Black Nylon Braided
Stainless Steel Braided

Increased Coolant Flow, Decreased Coolant Temperatures

The rear cylinders on the 5.9L Cummins suffer from a lack of coolant flow, and therefore, experience the highest coolant temperatures. This can cause excessive pressure to build in the cooling system, especially the rear of the block and blow out freeze plugs externally, or the smaller diameter plugs under the valve cover, leading to a failure. Our coolant bypass kit adds a secondary thermostat, that unlike other brands, works based on temperature instead of excessive pressure. This solves the problem before pressure becomes an issue by ensuring consistent temperatures across all six cylinders.

Fleece Performance Coolant Bypass Kit Features:

  • Lowers coolant temperature at the rear cylinders
  • Ensures consistent temperatures across all cylinders
  • Prevents damaging coolant pressure build up
  • Complete kit comes with braided hose and AN O-ring fittings to ensure a leak-free installation. Kits for MY 2003+ include billet hose brackets.
  • For more on Fleece's Performance Coolant Bypass Kit call us at 1-859-737-4966.


Why do I need a Fleece Coolant Bypass?

One of the biggest issues on the 5.9 Cummins is the coolant flow problem to the rear cylinders. This can cause catastrophic failure or blow outs of the freeze plugs in an over-temperature / over-pressure condition.  The Fleece Coolant Bypass is one of the most important additions you make to improve the reliability and longevity of the Cummins platform. 


  • Does this kit include the heater core tube as shown in video?

    JStorer | 1/13/2022

    No. Fleece does not include that tube any longer.