FLEECE FPE-CLNTBYPS-CUMMINS-MAN CUMMINS COOLANT BYPASS KIT 2003-2007 MANUAL TRANSMISSION

Keep rear-cylinder temps in check on your 2003–2007 5.9L Cummins (manual) with the FLEECE FPE-CLNTBYPS-CUMMINS-MAN Coolant Bypass Kit. A thermostatically controlled bypass improves flow at the back of the block to stabilize temperatures, protect freeze plugs, and add towing confidence without tuning. Fleece coolant bypass 5.9 cummins manual, rear cylinder cooling fix, secondary thermostat kit, 03 04 05 06 07 Dodge Ram 2500 3500, CPP Diesel Fleece Performance

Why it matters

• Addresses hot-spotting at cylinders #5/#6 for safer towing and sustained load
• Thermostat-based control opens with temperature (not pressure) for stable cooling
• Clean, bolt-on install with OE-quality components

Fitment

Engine: 5.9L Cummins (ISB), 24V
Vehicles: 2003–2007 Dodge Ram 2500/3500
Transmission: Manual transmission only

Cross-Reference / Related Fleece Items (CPP Diesel)

• FLEECE FPE-CLNTBYPS-CUMMINS-MAN-SS (Manual, stainless braided line)
• FLEECE FPE-CLNTBYPS-CUMMINS-0607 (Auto, 2006–2007)
• FLEECE FPE-CLNTBYPS-CUMMINS-0607-SS (Auto, 2006–2007, stainless)
• FLEECE FPE-CLNTBYPS-CUMMINS-12V-SS (12V 1994–1998, stainless)

The rear cylinders on the 5.9L Cummins run hotter due to limited coolant flow. This kit adds a controlled bypass to equalize temps and protect freeze plugs under load.

No tuning is required. The system is thermostat-activated and works with the factory cooling strategy.

No—this SKU is for manual transmissions. For automatic-equipped trucks, see the Auto versions listed above.

Thermostatic bypass assembly, hoses/lines, required fittings, and hardware. (Contents may vary; see product page for current contents.)

Specifications for FLEECE FPE-CLNTBYPS-CUMMINS-MAN