{"product_id":"fleece-coolant-bypass-kit-fpe-clntbyps-cummins-0305-2003-2005-5-9l-cummins-automatic-transmission","title":"FLEECE COOLANT BYPASS KIT FPE-CLNTBYPS-CUMMINS-0305 | 2003-2005 5.9L CUMMINS (AUTOMATIC TRANSMISSION)","description":"\u003cp\u003eImprove coolant circulation and maintain more consistent cylinder temperatures in your 2003–2005 Dodge Ram 5.9L Cummins with automatic transmission using the Fleece Performance FPE-CLNTBYPS-0305 Coolant Bypass Kit. Designed to improve coolant flow through the rear of the engine, this kit helps reduce temperature and pressure differences between the front and rear cylinders.\u003c\/p\u003e\n\u003cp\u003eThe factory cooling system can develop reduced coolant flow around the rear cylinders under demanding operating conditions. Increased heat can contribute to elevated coolant temperatures and pressure at the rear of the cylinder head, potentially increasing the risk of freeze plug and under-valve-cover plug failures.\u003c\/p\u003e\n\u003cp\u003eThe Fleece Coolant Bypass Kit uses a \u003cstrong\u003etemperature-activated secondary thermostat\u003c\/strong\u003e to provide additional coolant flow when needed. Unlike pressure-based bypass designs, the thermostat responds to coolant temperature to help maintain more consistent operating temperatures across all six cylinders.\u003c\/p\u003e\n\u003cp\u003eThe kit uses high-quality O-ring fittings and AN-style hose connections for a secure installation and is available with either \u003cstrong\u003ebraided black nylon or braided stainless steel hose\u003c\/strong\u003e. Installation does not require removal of the cylinder head.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eImproved rear-cylinder coolant flow\u003c\/strong\u003e – Helps maintain more consistent coolant temperatures across all six cylinders\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature-activated secondary thermostat\u003c\/strong\u003e – Provides additional coolant flow based on temperature rather than cooling-system pressure\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHelps control cooling-system pressure\u003c\/strong\u003e – Reduces excessive pressure buildup at the rear of the cylinder head\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo cylinder head removal required\u003c\/strong\u003e – Designed for installation without removing the cylinder head\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eO-ring fittings and AN connections\u003c\/strong\u003e – Provides secure coolant connections for reliable operation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo hose options\u003c\/strong\u003e – Available with braided black nylon or braided stainless steel hose\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1-year limited warranty\u003c\/strong\u003e – Covered according to current Fleece Performance warranty terms\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eApplication Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eFor automatic transmission-equipped trucks only.\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003eInstallation of this coolant bypass kit eliminates the factory transmission fluid heat exchanger.\u003c\/li\u003e\n\u003cli\u003eThe factory heat exchanger uses engine coolant to help warm the transmission fluid in cold operating conditions.\u003c\/li\u003e\n\u003cli\u003eConsider the vehicle's operating environment and transmission temperature requirements before removing the factory heat exchanger.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eFitment:\u003c\/strong\u003e 2003–2005 Dodge Ram 5.9L Cummins with Automatic Transmission\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePart Number:\u003c\/strong\u003e FPE-CLNTBYPS-CUMMINS-0305\u003c\/p\u003e","brand":"Fleece Performance Engineering","offers":[{"title":"Braided Black Nylon","offer_id":54105195643163,"sku":"FPE-CLNTBYPS-CUMMINS-0305","price":379.0,"currency_code":"USD","in_stock":true},{"title":"Braided Stainless Steel","offer_id":54105195675931,"sku":"FPE-CLNTBYPS-CUMMINS-0305-SS","price":379.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0962\/5757\/3147\/files\/Screenshot2026-10-05at11.17.38AM.png?v=1791220691","url":"https:\/\/wwmperformance.com\/products\/fleece-coolant-bypass-kit-fpe-clntbyps-cummins-0305-2003-2005-5-9l-cummins-automatic-transmission","provider":"WWM Performance","version":"1.0","type":"link"}