Interstate-McBee M-3975818 Engine Oil Cooler – 2007.5–2024 6.7L Cummins (Select 2003–2007 5.9L)

Heavy-duty, OEM-spec engine oil cooler designed to restore proper oil temperature control and pressure stability. The M-3975818 is a direct-fit aftermarket replacement for ISB/QSB applications and is widely used on 2007.5–2024 6.7L Cummins (Dodge Ram 2500/3500), with select fitment on 2003–2007 5.9L B-series/ISB when superseded by ESN. Always verify by engine serial number (ESN).

• Direct-fit replacement: Built to OEM dimensions for easy install and factory performance.
• Meets OEM specs: Quality materials and precise core construction for reliable cooling.
• Fixes common failures: Addresses restriction or internal leakage that elevates oil temps.
• Best practice: Replace related cooler-to-filter head and cooler-to-block gaskets during service.

Specifications

Vehicle Fitment

Confirm by ESN for exact applicability, especially on model-year splits and rebuilt engines.

• Dodge Ram 2500/3500 6.7L Cummins: 2007.5–2024 (ISB 6.7L)
• Dodge Ram 2500/3500 5.9L Cummins: 2003–2007 (select B-series/ISB applications where cooler supersedes)
• Notes: 2007 is a split year—early 2007 is 5.9L; mid-year (2007.5+) is 6.7L.

Installation Tips

• Drain oil and coolant as required; cap lines to prevent contamination.
• Replace both sealing gaskets (cooler→block and cooler→filter head).
• After any bearing/turbo failure, thoroughly flush the oil system and replace the filter.
• Prime the cooler with clean oil; follow Cummins service manual for torque specs and sequences.

Warranty

Interstate-McBee new engine parts carry manufacturer warranty coverage. Contact us with your ESN for assistance and exact terms.

Cross-Reference

Cummins 3975818 (primary), 3975817. Common legacy numbers: 3902372, 3902434, 3903375.

Recommended Add-Ons

• Interstate-McBee M-3974127 – Oil Cooler Gasket (to Filter Head)
• Interstate-McBee M-2830559 – Oil Cooler Gasket (to Engine Block)
• Fresh oil/filter; cooling system conditioner as required

FAQ