Fleece Performance

Cummins Coolant Bypass Kit 12V (1994-1998)

$359.00 $376.95


Increased Coolant Flow, Decreased Coolant Temperatures

The rear cylinders on the 5.9/6.7L 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.


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.

Online ordering will be available soon. Please call us at (206) 466-5274 or email us your order to .

Brand Fleece Performance
Shipping Weight 4.3 lb.
Shipping Width 12.1 in.
Shipping Length 15.6 in.
Shipping Height 3.1 in.
Warranty Yes
Warranty Info 1 Year Limited
Prop 65 WARNING: Cancer & Reproductive Harm - P65Warnings.ca.gov
Year Make Model Engine
1994 Cummins 2500 Cummins 5.9L
1994 Cummins 3500 Cummins 5.9L
1995 Cummins 2500 Cummins 5.9L
1995 Cummins 3500 Cummins 5.9L
1996 Cummins 2500 Cummins 5.9L
Year Make Model Engine
1996 Cummins 3500 Cummins 5.9L
1997 Cummins 2500 Cummins 5.9L
1997 Cummins 3500 Cummins 5.9L
1998 Cummins 2500 Cummins 5.9L
1998 Cummins 3500 Cummins 5.9L


Diesel Dudes LLC is fueled by solid communication and proven performance in building diesel engines and trucks - honestly and expertly in Seattle.



1420 S Henderson St
Seattle, WA 98108



(206) 466-5274
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