Product Description
Cummins 3959574 — Piston Cooling Nozzle Plug (Oil Squirter Delete)
MPN: 3959574 | Also Known As: piston cooling plug, oil squirter delete plug | Cross-Refs: 3954839, 4896153
Why This Part
- ✓ OE Cummins plug for servicing/plugging piston cooling jet bores.
- ✓ Direct-fit on ISB/QSB platforms; common on Ram 5.9L/6.7L builds.
- ✓ Controls oil flow when deleting oil squirters in race applications.
- ✓ Helps maintain stable oil pressure after block machining or repair.
Quick Specs
| Type | Piston cooling nozzle plug (oil squirter delete) |
|---|---|
| OE Part # | 3959574 (cross-refs: 3954839, 4896153) |
| Typical Qty | As needed; up to 6 per engine if deleting all jets |
| Usage | Service/repair or performance delete; confirm by ESN |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
| 2007.5–2018 | Ram 6.7L ISB (24V Common-Rail) | Ram 2500/3500 |
Notes: Cummins catalogs indicate 3959574 is used primarily on Tier 3/EPA13 ISB/QSB 6.7 applications; many builders also use it on 2003–2007 5.9L for service or race-only delete. Always verify by ESN/VIN and your build goals.
Often Paired With
- Piston Cooling Nozzle (restore, not delete): Cummins 4937308 (’03–’18 ISB/QSB)
- Engine oil & filter after any bottom-end service
What’s In The Box
- (1) Genuine Cummins Piston Cooling Plug (3959574)
- Quantity as needed (sold individually).
Install Tips
- Confirm ESN and block style; clean bores thoroughly before install.
- Follow Cummins service information for plug seating/orientation.
- After assembly, verify oil pressure and inspect for leaks on warm-up.
FAQ
WILL THIS FIT MY 2003–2018 RAM 5.9L/6.7L?Commonly used on 2003–2007 5.9L and 2007.5–2018 6.7L ISB engines. Cummins notes primary use on ISB/QSB 6.7 (Tier 3/EPA13). Verify by ESN before ordering.
HOW MANY PLUGS DO I NEED?As needed—typically up to 6 per engine if deleting all piston cooling nozzles. Some builds use fewer; follow your engine builder’s plan.
IS THIS FOR STREET USE?Deleting oil squirters is usually a race-only modification. For restoration/stock use, choose the OEM nozzle (e.g., 4937308) instead of plugs.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3959574 piston cooling plug with correct fit and material.
WHAT ARE THE CROSS-REFERENCE NUMBERS?Common cross-refs: 3954839 and 4896153 (used by gasket kits and aftermarket catalogs).
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Happy with my purchase.
Item was as described and arrived sooner than expected.
