INTERSTATE-MCBEE M-3959031 OIL COOLER 03-07 5.9L CUMMINS (AFTERMARKET REPLACEMENT)

Product Description

Interstate-McBee M-3959031 Oil Cooler — 2003–2007 5.9L Cummins (24-Valve Common Rail)

Direct-replacement engine oil cooler for the 2003–2007 Dodge Ram 2500/3500 with the 5.9L Cummins ISB (24-valve common rail). Restores proper oil temperature control and protects bearings, turbocharger, and valvetrain from heat-related wear. Aftermarket replacement; built to OE form, fit, and function.

• OE-style performance: Matches factory flow and heat-transfer characteristics.
• Reliable construction: Precision-brazed core and robust end plates for long service life.
• Drop-in fit: Bolts up to the factory oil cooler housing; no modifications required.

What’s Included

• (1) Oil cooler assembly, P/N M-3959031

Note: Gaskets/seals and the cooler cover/housing are typically not included unless specified. Add a fresh gasket/seal kit during installation.

Vehicle Fitment

Always verify by engine serial number (ESN) when possible.

• Dodge Ram 2500/3500 with 5.9L Cummins ISB (24-valve common rail)
  • Model Years: 2003, 2004, 2005, 2006, 2007 (5.9L)
• Additional ISB 5.9L industrial/medium-duty applications where Cummins 3959031 is specified (confirm by ESN).

Recommended/Related Parts

• Oil cooler gasket/seal kit (order for your ESN)
• Engine oil filter and fresh oil (for post-service refill)
• Coolant (if drained during service)

Install Notes

• Allow the engine to cool; drain oil and, if necessary, coolant.
• Clean mating surfaces thoroughly; do not reuse crushed or swollen seals.
• Torque fasteners to factory specification and follow the Cummins service manual procedure.
• After installation, prime the oil system and check for leaks at idle until operating temperature is reached.

Why Buy From CPP Diesel

• ESN-verified fitment support from diesel specialists
• Fast shipping and competitive pricing
• Deep inventory of complementary ISB service parts

FAQ

Will this fit my 2003–2007 5.9L Cummins?

Yes—this cooler is intended for the 24-valve common-rail 5.9L ISB used in 2003–2007 Dodge Ram 2500/3500. For other ISB applications, verify by ESN.

Do I need new gaskets?

Yes. Always install new gaskets/seals when replacing the oil cooler to prevent leaks.

Is this an OEM Cummins part?

No—this is an Interstate-McBee aftermarket replacement built to OE fit and function.