This Wehrli Custom Fabrication (WCFab) thin-flange coolant fitting is engineered specifically for the coolant port located behind the water pump on 6.7L Cummins engines. Precision CNC machined from billet aluminum, it provides a robust connection compared to standard fittings. The design utilizes a press-fit connection secured by a high-temperature O-ring seal and an integrated mounting bolt tab to ensure a leak-free seat even under high thermal stress.

• Fits 6.7L Cummins engines
• #10 JIC Male fitting for simplified plumbing
• CNC machined from high-grade billet aluminum
• Durable black anodized finish for corrosion resistance
• High-temperature O-ring seal included
• Integrated mounting bolt tab for secure installation
• Made in the USA
• Manufacturer Part Number: WCF205-136

Fits select 2007-2018 Dodge and Ram 2500/3500 trucks equipped with the 6.7L Cummins diesel engine.

The Fleece Performance Exhaust Back Pressure (EBP) Relocation Kit allows you to move the sensitive EBP sensor from its factory location on the thermostat housing elbow to a cooler, more accessible mounting block on the front side of the radiator. This kit is essential for managing heat-related sensor wear and simplifies engine bay maintenance. It serves as a direct replacement for the relocation hardware found in the FPE-CLNTBYPS-CUMMINS-0712 coolant bypass kit.

• Relocates EBP sensor to cooler mounting location on the radiator
• Includes EBP sensor mounting block
• Includes exhaust manifold pressure feed tube
• Fits 6.7L Cummins engines from 2007-2018
• Manufacturer Part Number: FPE-CUMM-EBP-KIT-0712

This Wehrli Custom Fabrication coolant plug is designed to securely block off the 1.1-inch bore on Duramax engine covers. Precision CNC-machined from high-grade billet aluminum, this component offers a significant upgrade in durability and aesthetics compared to generic alternatives.

The plug features a sleek black anodized finish, providing excellent resistance to corrosion and wear in high-heat engine bay environments. For a reliable, leak-free installation, the assembly includes a high-temperature silicone O-ring specifically chosen to withstand the thermal cycles of a heavy-duty diesel engine.

• Material: CNC-machined billet aluminum
• Finish: Black anodized for corrosion resistance
• Bore Compatibility: 1.1"
• Hardware: Includes high-temperature silicone O-ring seal
• Application: Duramax Engine Cover
• Manufacturer Part Number: WCF100025

Simplify your coolant system plumbing with the Fleece Performance FPE-34258-A universal pre-formed hose kit. Designed to solve the routing challenges of custom engine builds and cooling system modifications, this 5/8" ID hose features molded 90-degree ends that maintain full flow without the kinking or collapsing common when using standard straight hoses in tight spaces.

This kit includes a heavy-duty T-fitting with a 1" ID main bore, providing a secure junction for integrating heater circuits, bypass lines, or expansion tanks. The pre-formed architecture ensures a professional, factory-style finish for any custom automotive cooling application where clean routing is a priority.

• Manufacturer Part Number: FPE-34258-A
• Hose Size: 5/8" Internal Diameter (ID)
• Ends: Dual pre-formed 90-degree bends
• Included Fitting: 1" ID T-Fitting
• Application: Universal coolant and heater hose routing

Designed for high-performance 6.7L Cummins applications, this Wehrli Custom Fab #12 JIC male fitting provides a secure, leak-free solution for the coolant port located behind the water pump. This fitting is an essential upgrade for custom cooling setups requiring a reliable JIC interface.

Precision CNC machined from high-grade billet aluminum, the fitting features a thick flange and an integrated mounting bolt tab to ensure the connection remains stable under vibration and pressure. The press-fit design incorporates a high-temperature O-ring seal to withstand the extreme thermal cycles common in diesel environments, finished with black anodizing for long-term corrosion resistance.

• CNC machined billet aluminum construction
• #12 JIC male fitting for custom coolant plumbing
• High-temperature O-ring seal for reliable performance
• Integrated mounting bolt tab for secure retention
• Durable black anodized finish
• Made in the USA
• Manufacturer Part Number: WCF205-140

Fits 1998-2002 Dodge Ram 2500 and 3500 (5.9L / 6.7L).

The rear cylinders on 5.9L and 6.7L Cummins engines often suffer from restricted coolant flow, leading to significantly higher temperatures at the back of the block. This thermal imbalance creates excessive pressure that can blow out external freeze plugs or the smaller diameter plugs located under the valve cover. The Fleece Performance VP Coolant Bypass Kit addresses this cooling deficiency at the source.

Unlike other systems that react only to excessive pressure, this kit features a secondary thermostat that operates based on coolant temperature. By opening at a set temperature, it ensures consistent flow and thermal stability across all six cylinders before pressure reaches dangerous levels. The kit includes high-quality stainless steel braided lines and AN O-ring fittings to provide a secure, leak-free connection. Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-VP-SS.

• Prevents damaging coolant pressure buildup at the rear of the engine block
• Lowers coolant temperatures at the rear cylinders for improved engine longevity
• Ensures consistent operating temperatures across the entire cylinder head
• Temperature-controlled secondary thermostat for proactive cooling management
• Complete kit includes stainless steel braided hose and AN O-ring fittings

Fits 1998-2002 Dodge Ram 2500 and 3500 (5.9L / 6.7L).

The rear cylinders on the 5.9L and 6.7L Cummins engines often suffer from restricted coolant flow, leading to localized hot spots and excessive pressure buildup at the back of the block. This thermal stress can result in catastrophic failure, including blown external freeze plugs or the smaller diameter plugs located under the valve cover. The Fleece Performance VP Coolant Bypass Kit addresses this design flaw by integrating a secondary thermostat that operates based on coolant temperature rather than just pressure. This ensures consistent cooling across all six cylinders and relieves the pressure before it reaches critical levels.

• Regulates coolant temperature at the rear cylinders to improve engine longevity
• Secondary thermostat design ensures cooling based on temperature for consistent performance
• Prevents damaging pressure buildup that leads to freeze plug failure
• High-quality braided hose with AN O-ring fittings for a secure, leak-free seal
• Complete installation kit specifically designed for VP-series Cummins applications
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-VP

Fits select 1994-2018 Dodge and Ram 2500/3500 trucks.

Maintain the efficiency of your cooling system with the Fleece Performance Coolant Bypass Service Kit. This complete maintenance package includes the essential seals and hardware required to refresh your Fleece Coolant Bypass system, ensuring long-term reliability and preventing leaks at critical connection points. The kit is designed to be universal for all Fleece bypass production years by including two different thermostats; you will select and install the one that matches your specific bypass housing.

Note: This kit is designed specifically for servicing the Fleece Performance bypass assembly and does not include the primary Cummins engine thermostat. Depending on your specific kit version (such as 1994-2002 models), some included O-rings may not be required for your application.

• Complete set of replacement fasteners
• 2 thermostats (use one depending on production year)
• 3 new square-cut O-rings
• 1 new standard O-ring
• 2 new O-rings for each AN fitting
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-SER-KIT

Fits 2003-2007 Dodge Ram 2500 and 3500 models equipped with manual transmissions (6.7L).

The rear cylinders on the 5.9L and 6.7L Cummins engines often suffer from restricted coolant flow, leading to the highest operating temperatures at the back of the block. This thermal imbalance can cause excessive pressure to build, potentially blowing out external freeze plugs or the smaller diameter plugs located under the valve cover. The Fleece Performance coolant bypass kit addresses this vulnerability by adding a secondary thermostat. Unlike other kits that rely on pressure alone, this system is temperature-actuated, opening to ensure consistent coolant flow across all six cylinders before pressure becomes a problem.

This kit improves the long-term reliability and cooling efficiency of the Cummins platform, protecting the engine from catastrophic failure during high-load or over-temperature conditions. Each kit includes a high-quality stainless steel braided hose and AN O-ring fittings to ensure a secure, leak-free installation.

• Lowers coolant temperatures at the rear cylinders
• Ensures consistent thermal profiles across the entire engine block
• Prevents damaging pressure buildup and freeze plug failure
• Includes stainless steel braided line and AN O-ring fittings
• Temperature-based thermostat operation for proactive cooling
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-MAN-SS

Fits 2003-2007 Dodge Ram 2500 and 3500 models equipped with a manual transmission (5.9L / 6.7L Cummins).

The rear cylinders on the 5.9L and 6.7L Cummins engines frequently suffer from inadequate coolant flow, leading to significantly higher temperatures at the back of the block. This thermal imbalance creates excessive pressure that can blow out freeze plugs externally or smaller plugs located under the valve cover, often resulting in catastrophic engine failure. The Fleece Performance Coolant Bypass Kit is a critical reliability upgrade designed to normalize temperatures across all six cylinders.

Unlike other bypass kits that operate solely on pressure, this system utilizes a secondary thermostat that opens based on coolant temperature. This proactive approach ensures consistent flow and prevents pressure spikes before they can damage your engine components. The kit is built for long-term durability with high-quality materials to ensure a leak-free installation.

• Lowers coolant temperatures at the vulnerable rear cylinders
• Ensures consistent thermal management across the entire engine block
• Prevents damaging coolant pressure buildup and freeze plug failure
• Includes high-quality braided hose and AN O-ring fittings for a secure seal
• Secondary thermostat-controlled operation for precise cooling
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-MAN

Fits select 2019-2022 Ram 2500 and 3500 trucks equipped with the 6.7L Cummins engine.

The 6.7L Cummins engine often suffers from inadequate coolant flow to the rear cylinders, leading to localized hot spots and excessive pressure build-up. This thermal imbalance can cause external freeze plugs to blow or, more critically, dislodge the smaller diameter plugs located under the valve cover. The Fleece Performance Coolant Bypass Kit addresses this vulnerability with a patent-pending design that integrates a secondary thermostat. Unlike other kits that rely on pressure relief, this system operates based on temperature, ensuring consistent coolant flow across all six cylinders before pressure becomes a factor.

Built for long-term reliability and an OE-style fit, this kit includes high-quality braided hoses and AN O-ring fittings to provide a secure, leak-free seal. By stabilizing temperatures at the rear of the block, you protect your engine from catastrophic failure and improve the overall longevity of the cooling system.

• Improved Cooling: Lowers coolant temperatures at the rear cylinders by increasing flow.
• Temperature-Based Control: Secondary thermostat activates based on heat rather than waiting for pressure spikes.
• Consistent Thermal Gradient: Ensures even temperatures across the entire cylinder head.
• Durable Construction: Includes braided hose and AN O-ring fittings for maximum leak protection.
• MPN: FPE-CLNTBYPS-CUMMINS-19

Fits 2013-2018 Ram 2500 and 3500 (6.7L).

The 6.7L Cummins engine often suffers from restricted coolant flow to the rear cylinders, leading to localized overheating and excessive pressure buildup. This thermal stress can cause external freeze plugs to fail or blow out the smaller diameter plugs located under the valve cover. The Fleece Performance Coolant Bypass Kit addresses this design flaw by adding a secondary thermostat at the rear of the block.

Unlike pressure-relief style kits that only react once a problem exists, this temperature-based bypass ensures consistent coolant flow across all six cylinders. By opening based on temperature, it proactively regulates heat at the rear of the engine, protecting your cooling system and improving long-term reliability. The kit features an OE-style fit and finish with high-quality components designed for a leak-free installation.

• Thermostat Regulation: Uses a temperature-sensitive secondary thermostat for proactive cooling management.
• Leak-Free Seal: Includes AN O-ring fittings and a black braided nylon coolant hose.
• Thermal Protection: Prevents damaging pressure buildup and freeze plug blowouts.
• Complete Kit: Includes front and rear thermostat housings, EGR crossover tube gaskets, high-temperature protective hose sleeve, and all necessary mounting hardware.
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-1318

Fits 1994-1998 Dodge Ram 2500 and 3500 (5.9L / 6.7L).

The rear cylinders on the Cummins block often suffer from restricted coolant flow, leading to localized hotspots and excessive pressure build-up. This thermal imbalance can result in catastrophic failure, including blown external freeze plugs or the smaller plugs located under the valve cover. The Fleece Performance 12V Coolant Bypass Kit addresses this design flaw at the source to improve the reliability and longevity of your engine.

Unlike pressure-based systems from other brands, this kit utilizes a secondary thermostat that reacts to actual coolant temperature. This ensures consistent cooling across all six cylinders by allowing flow before pressure reaches critical levels. The kit features high-quality stainless steel braided lines and AN O-ring fittings to provide a secure, leak-free connection that replaces the factory shortcomings.

• Lowers coolant temperatures at the rear cylinders
• Ensures consistent thermal management across all cylinders
• Prevents damaging pressure build-up and freeze plug failure
• Temperature-based secondary thermostat for proactive cooling
• Complete kit with heavy-duty stainless steel braided hose
• Leak-free AN O-ring fittings included
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-12V-SS

Fits 1994-1998 Dodge Ram 2500 and 3500 (5.9L / 6.7L Cummins).

The rear cylinders on the Cummins engine platform often suffer from restricted coolant flow, leading to localized hot spots and excessive cooling system pressure. If left unaddressed, this pressure can result in catastrophic failure by blowing out external freeze plugs or the smaller plugs located under the valve cover. The Fleece Performance Coolant Bypass Kit is a proactive solution designed to improve the reliability and longevity of your engine.

Unlike other kits that rely on pressure-activated valves, this kit utilizes a secondary thermostat that operates based on temperature. This design ensures consistent coolant flow across all six cylinders, resolving temperature imbalances before damaging pressure builds up. It is a vital upgrade for high-horsepower applications or vehicles operating in demanding environments.

• Lowers coolant temperatures at the rear cylinders
• Ensures consistent temperature distribution across the entire block
• Prevents damaging pressure buildup that leads to freeze plug failure
• Includes high-quality braided hose and AN O-ring fittings for a leak-free seal
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-12V

Fits select 2007-2012 Dodge/Ram 2500 and 3500 models with the 6.7L Cummins engine.

The 6.7L Cummins engine is known for cooling deficiencies at the rear of the block, where cylinders five and six often suffer from stagnant coolant flow. These localized high temperatures create excessive pressure that can lead to catastrophic freeze plug failure—both externally and under the valve cover. The Fleece Performance Coolant Bypass Kit (MPN: FPE-CLNTBYPS-CUMMINS-0712) addresses this design flaw by establishing a secondary flow path.

Unlike pressure-relief style kits, this system uses a secondary thermostat that operates based on actual coolant temperature. This ensures consistent thermal management across all six cylinders, preventing pressure spikes before they occur. The kit features high-quality braided nylon hose with a protective high-temperature sleeve and AN O-ring fittings for a leak-free, OE-style integration.

• Lowers coolant temperatures at the rear cylinders
• Ensures consistent temperature distribution across the entire block
• Prevents freeze plug blowouts caused by localized pressure buildup
• Includes secondary thermostat for temperature-regulated bypass
• Braided nylon hose with AN fittings for long-term durability

Kit Includes: Rear coolant bypass thermostat housing, front coolant bypass thermostat housing, EGR crossover tube gaskets, braided nylon coolant bypass hose with high-temp sleeve, exhaust back pressure sensor mounting block with line, and all necessary mounting hardware.

Fits 2006-2007 Dodge Ram 2500 and 3500 models with automatic transmissions (5.9L / 6.7L).

The rear cylinders on 5.9L and 6.7L Cummins engines frequently suffer from inadequate coolant flow, leading to localized hotspots and excessive pressure. This pressure can cause catastrophic failure, including blown external freeze plugs or the smaller diameter plugs located under the valve cover. The Fleece Performance Coolant Bypass Kit addresses this by adding a secondary thermostat that operates based on temperature rather than pressure, ensuring consistent cooling across all six cylinders and protecting your engine from over-temperature conditions.

This comprehensive kit features high-quality AN O-ring fittings and a durable stainless steel braided hose for a reliable, leak-free installation. For 2003-2007 5.9L automatic transmission applications, note that this kit is designed to eliminate the factory transmission fluid heat exchanger, which is typically used for warming fluid in cold climates.

• Lowers coolant temperatures at the rear of the engine block
• Prevents damaging pressure buildup that leads to freeze plug failure
• Secondary thermostat ensures flow based on temperature for consistent cooling
• Stainless steel braided coolant line with billet hose brackets
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-0607-SS

Fits select 2006-2007 Dodge Ram 2500 and 3500 trucks (5.9L / 6.7L Cummins) equipped with automatic transmissions.

The rear cylinders on the Cummins 5.9L and 6.7L engines often suffer from restricted coolant flow, leading to localized hotspots and elevated temperatures at the back of the engine block. This heat buildup creates excessive cooling system pressure that can eject external freeze plugs or the smaller diameter plugs located under the valve cover. The Fleece Performance Coolant Bypass Kit solves this by adding a secondary thermostat that operates based on coolant temperature rather than pressure, ensuring consistent flow across all six cylinders and preventing catastrophic failure.

For 2006-2007 5.9L automatic transmission applications, this kit is designed to eliminate the factory transmission fluid heat exchanger. Originally intended for warming transmission fluid in extreme cold, this exchanger is not necessary in warmer climates or high-horsepower builds and its removal does not negatively affect vehicle performance.

• Reduces coolant temperatures at the rear cylinders for improved engine longevity
• Ensures consistent operating temperatures across the entire engine block
• Prevents damaging pressure spikes that lead to freeze plug failure
• High-quality braided hose and AN O-ring fittings ensure a leak-free installation
• Billet hose brackets included for a secure, professional fit
• Manufacturer Part Number: FPE-CLNTBYPS-CUMMINS-0607

Fits 2003-2005 Dodge Ram 2500 and 3500 trucks (5.9L / 6.7L) equipped with automatic transmissions.

The rear cylinders on the Cummins 5.9L and 6.7L engines often suffer from restricted coolant flow, resulting in significantly higher temperatures at the back of the block. This heat soak can cause excessive pressure buildup, leading to blown external freeze plugs or the failure of smaller plugs located under the valve cover. The Fleece Performance Coolant Bypass Kit addresses this design flaw by adding a secondary thermostat. Unlike pressure-relief systems, this kit operates based on coolant temperature, ensuring consistent cooling across all six cylinders and preventing pressure spikes before they cause damage.

This specific kit for 2003-2005 automatic transmission models is designed to eliminate the factory transmission fluid heat exchanger. This is an essential upgrade for high-horsepower applications or trucks operating in warmer climates where the factory heater-assisted warm-up is unnecessary. The kit features high-quality AN O-ring fittings and braided hoses to ensure a leak-free seal and includes billet hose brackets for a clean, professional install.

• Lowers coolant temperatures at the rear cylinders to improve engine longevity
• Secondary thermostat ensures consistent temperature across the entire block
• Prevents damaging pressure buildup that leads to blown freeze plugs
• Complete kit includes braided hose and AN O-ring fittings
• Includes billet hose brackets for a secure installation
• Replaces manufacturer part number: FPE-CLNTBYPS-CUMMINS-0305

Fits select 1994-2018 Dodge and Ram 2500/3500 trucks (Cummins) equipped with a Fleece Performance Coolant Bypass Kit.

Keep your Cummins cooling system operating at peak efficiency with this genuine Fleece Performance replacement O-ring kit. Designed as a direct service solution for all Fleece Cummins Coolant Bypass Kits, this set ensures a leak-free seal when performing maintenance or reinstalling your bypass system. This kit provides the exact tolerances required to maintain system pressure and prevent coolant loss at critical connection points.

While this comprehensive kit is designed to cover multiple generations of bypass systems, please note that when used with 1994-2002 model year kits, not all included O-rings will be utilized.

• Includes three (3) square cut O-rings
• Includes one (1) standard O-ring
• Includes two (2) AN fitting O-rings
• Restores factory-level sealing for coolant bypass components
• Manufacturer Part Number: FPE-CLNTBYPS-CR-ORING-KIT

Fits select 2003-2007 Dodge Ram 2500 and 3500 models with Cummins engines.

Secure your aftermarket cooling system components with this set of Fleece Performance Cummins Coolant Bypass Brackets. Specifically designed for 5.9L Cummins applications, these brackets provide the necessary support for bypass lines and housings, ensuring they remain stable under high-pressure and high-vibration conditions. By maintaining proper alignment and preventing hose movement, these brackets help eliminate potential chafing and fatigue-related failures in the cooling system.

• Direct fit for 2003-2007 Dodge Ram 2500/3500 Cummins diesel engines
• Heavy-duty construction for long-term durability and resistance to engine bay heat
• Includes two (2) brackets for a complete installation
• Designed for use with Fleece Performance coolant bypass systems
• Manufacturer Part Number: FPE-CLNT-HS-BRKT

Fits 2013-2018 Ram 2500 and 3500 models equipped with the 6.7L Cummins diesel engine.

When upgrading to a 2nd Gen turbo swap or a compound turbo configuration, the factory air conditioning lines often create significant interference issues. This Fleece Performance A/C Line Reroute Kit is engineered to relocate these lines, providing the necessary clearance for larger turbochargers, aftermarket manifolds, and custom piping. By rerouting the lines, you ensure a professional installation that avoids heat damage and physical contact with forced induction components while maintaining full A/C functionality.

• Specifically designed for 2nd Gen Swap and Compound Turbo setups
• Clears space for larger aftermarket turbochargers and manifolds
• Direct fit for 2013-2018 Ram 2500/3500 6.7L Cummins
• Manufacturer Part Number: FPE-AC-KIT-1316