Vendor : Fleece Performance
Product Type : Engines
Sku : FPEFPE-LSR-FMJ-SD10X
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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. Benefits: 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. Why do I need a Fleece Coolant Bypass? One of the biggest issues on the 5.9/6.7L 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. Application Notes: The 2003 - 2007 5.9L automatic transmission version will eliminate the factory transmission fluid heat exchanger. The heat exchanger is designed for use in cold climates to warm the transmission fluid with the engine coolant.
WarrantyWe will be temporarily closed from Monday 10th August until Friday 21st August 2026 while we relocate to our new premises and carry out our annual stock take. Our website will remain open and you are welcome to place orders during this period. However, new orders placed between 11th and 21st August will not be processed or dispatched until we reopen. Please note: Any orders currently open and already in our system will continue to be processed as normal and will not be affected by the temporary closure. If you have an urgent order or require something that cannot wait until we reopen, please contact us via our website chat or email. We will do our best to assist wherever possible. Normal service will resume on Saturday 22nd August 2026. We apologise for any inconvenience this may cause and greatly appreciate your patience and continued support while we complete our relocation and annual stock take. Thank you for your understanding and continued support.
