Product Description

FLEECE FPE-CLNTBYPS-CUMMINS-0305-SS CUMMINS COOLANT BYPASS KIT 2003-2005 AUTO TRANS WITH STAINLESS STEEL BRAIDED LINE

The FLEECE FPE-CLNTBYPS-CUMMINS-0305-SS Coolant Bypass Kit is engineered to solve one of the most common cooling system weak points on 2003–2005 5.9L Cummins engines—unbalanced rear-cylinder cooling that leads to hotter EGT, higher coolant temps, and head gasket stress. This stainless-steel braided bypass adds a dedicated flow path from the rear of the cylinder head, helping stabilize coolant pressure, reduce temperature spikes, and improve long-term engine reliability under towing, hauling, and tuned performance applications. Fleece FPE-CLNTBYPS-CUMMINS-0305-SS coolant bypass kit, 2003 2004 2005 Cummins coolant bypass, 5.9L Cummins coolant mod, stainless steel coolant bypass Cummins, CPP Diesel Fleece bypass kit, rear head coolant flow fix, Cummins cooling upgrade

This kit is specifically designed for **automatic-transmission** 2003–2005 Dodge/Ram Cummins trucks and includes a durable stainless-steel braided hose for maximum heat resistance and long-term durability. Whether your Cummins is stock, towing hard, or making big power, this bypass system helps maintain safe, balanced cooling throughout the entire head.

FEATURES

• Improves rear-cylinder coolant flow for more uniform engine temperatures
• Helps reduce head-gasket stress under towing and performance use
• Stainless-steel braided coolant line provides maximum durability and heat resistance
• Direct bolt-on design—no cutting, drilling, or fabrication
• Designed specifically for 2003–2005 Cummins with automatic transmission
• Includes all fittings, hardware, and brackets required for installation

FITMENT

• Engine: 5.9L Cummins Turbo Diesel
• Model Years: 2003, 2004, 2004.5, 2005
• Vehicle: Dodge / Ram 2500 & 3500
• Transmission: **Automatic transmission only**
• Not recommended for manual-trans trucks (requires different bypass configuration)

CROSS-REFERENCE & RELATED FLEECE PRODUCTS

Pair this coolant bypass kit with these Fleece cooling and Cummins components available at CPP Diesel:

• 2006–2007 Cummins coolant bypass kit:
  FLEECE FPE-CLNTBYPS-CUMMINS-0607-SS COOLANT BYPASS KIT 2006–2007
• 2003–2018 CP3 feed fitting:
  FLEECE FPE-CP3-FEED 1/2 INCH CP3 FEED FITTING
• High-Flow Feed Line Kit (2010–2018):
  FLEECE FPE-HFFL-1018 HIGH FLOW FEED LINE KIT
• Cummins Dual Pump Controller:
  FLEECE FPE-CDPC CUMMINS DUAL PUMP CONTROLLER

FAQ

Why do I need a coolant bypass kit on my 5.9L Cummins?

The rear cylinders of the 5.9L Cummins suffer from restricted coolant flow, which causes higher temps and pressure spikes. This bypass kit relieves rear-cylinder heat, stabilizes coolant pressure, and reduces head-gasket stress.

Is this version only for automatic-transmission trucks?

Yes. This FPE-CLNTBYPS-CUMMINS-0305-SS kit is matched specifically to the 2003–2005 automatic-trans cooling system layout. Manual-trans trucks require a different routing and kit design.

Does this help with towing and heavy hauling?

Absolutely. Towing amplifies heat in the rear cylinders. This bypass improves coolant balance, especially under high-load conditions like towing, hauling, or higher EGT driving.

Do I need special tools for installation?

No specialty tools are required. This kit is a direct bolt-on upgrade and includes all necessary fittings, brackets, and hardware.

Is there a Prop 65 warning for this product?

Yes — certain components may expose you to chemicals known to the State of California to cause cancer or reproductive harm. www.P65Warnings.ca.gov

Specifications for FLEECE FPE-CLNTBYPS-CUMMINS-0305-SS