Product Description
Interstate-McBee M-3959574 Piston Cooling Plug – 03–18 5.9L/6.7L Cummins
OE-style piston cooling nozzle block-off plug engineered by Interstate-McBee for 2003–2018 Cummins 5.9L & 6.7L ISB applications. Used to seal the unused piston oil jet passage on blocks with dual drillings (saddle-jet vs. bolt-in “J-jet”). Helps maintain proper oil pressure and thermal management during service or performance builds.
- Direct replacement: Matches Cummins 3959574 dimensions for a precise fit.
- Proper oil control: Seals the unused cooling-jet passage to help prevent oil pressure loss.
- Durable materials: Built to OE-level standards for reliable, long-term sealing.
- Aftermarket value: Interstate-McBee quality at a budget-friendly price point.
Specifications
| Interstate-McBee P/N | M-3959574 |
|---|---|
| OEM Cross-Reference | 3959574 (Cummins); additional refs: 3954839, 4896153 |
| Engine Family | Cummins B-Series ISB/QSB |
| Typical Qty/Engine | 6 (varies by configuration) |
| Function | Piston cooling nozzle block-off (unused passage) |
Vehicle Fitment
Verify by engine serial number (ESN) and block configuration.
- Dodge Ram 2500/3500 5.9L Cummins (Common-Rail): 2003–2007
- Dodge Ram 2500/3500 6.7L Cummins: 2007.5–2018 (Tier 3/ISB applications; confirm dual-drilling block)
- Industrial/Off-Highway ISB/QSB: Usage where Cummins 3959574 applies (check ESN and service manual)
Install Notes
- Identify which piston cooling system is present (saddle-jet vs. bolt-in J-jet).
- On dual-drilled blocks, install this plug in the unused passage to maintain oil pressure.
- Follow Cummins service procedures and torque specs; use new seals/hardware as specified.
What’s Included
- (1) Piston cooling passage plug (M-3959574)
Why Buy From CPP Diesel
- ESN-verified fitment support for Cummins B-Series engines
- Fast shipping and hassle-free returns
- Expert tech guidance for street, tow, and performance builds
FAQ
How many plugs does my engine need?Common-rail B-Series typically use six plugs (one per cylinder) when the unused passage is present. Always confirm your block’s configuration.
Will this fit both 5.9L and 6.7L?
Yes—on Cummins 5.9L (2003–2007) and many 6.7L (2007.5–2018) ISB engines that have dual drillings for piston oil jets. Verify by ESN and service documentation.
Is this a “delete” for piston cooling jets?
No—this plug seals the unused passage on dual-drilled blocks. If converting jet styles or building performance engines, follow factory guidance to retain adequate piston cooling and oil pressure.
What are the OEM cross-references?
Cummins 3959574 (also cataloged with 3954839 and 4896153 in some references).
