Product Description
CUMMINS 3973512 OEM ENGINE OIL CAP O-RING – RAM 5.9L/6.7L (1998.5–2025)
The genuine Cummins 3973512 engine oil fill cap O-ring is the factory correct seal designed to restore a leak-free, OEM-tight seal at the oil fill cap on 5.9L and 6.7L Ram Cummins engines (1998.5–2025). This direct-fit replacement prevents oil mist or drips around the valve cover, preserves engine bay cleanliness, and protects internal components from contamination — giving you reliable, long-term performance from your diesel engine. Built by Cummins using durable elastomer material resistant to heat, oil, and repeated cap cycles, this O-ring ensures proper sealing under stock or service conditions.
Fitment / Vehicle Compatibility
- 1998.5–2002 Ram 5.9L ISB (24-valve VP44)
- 2003–2007 Ram 5.9L ISB (Common-Rail)
- 2007.5–2025 Ram 6.7L ISB (Common-Rail)
Always verify by VIN / Engine Serial Number (ESN) before ordering — though this O-ring is widely used across ISB 5.9L & 6.7L engines during the above years.
Why Choose This O-Ring
- OEM-exact part from Cummins — not aftermarket guesswork.
- Direct-fit: installs in the original oil fill cap without modification.
- Cost-effective leak fix — often replaces messy oil leaks for under $10.
- OEM quality elastomer resists oil, heat, and repeated use for long service life.
Often paired with the matching oil fill caps when replacing the seal:
Installation / Maintenance Notes
Before installing, clean the oil cap groove and valve cover sealing surface thoroughly to remove oil residue or debris. Lightly coat the new O-ring with clean engine oil and seat it evenly — do not stretch or twist. After installation and running the engine, inspect around the filler cap to ensure there is no oil mist or seepage. No RTV or additional sealant is required.
FAQ WILL THIS FIT MY 5.9L OR 6.7L CUMMINS RAM?
Yes — this O-ring fits most 1998.5–2025 Ram 2500/3500 5.9L & 6.7L applications. Always verify by VIN/ESN if components have been changed. WHAT SYMPTOMS POINT TO A BAD OIL CAP O-RING?
Oil mist or drips around the cap/valve cover, or the cap feeling loose. Replacing the O-ring usually fixes it. IS THIS A GENUINE CUMMINS PART?
Yes — this is the factory Cummins part (P/N 3973512). DO I NEED ANY SEALANT?
No — install dry or with a light film of clean oil. No RTV or sealant is required. WHAT OIL FILL CAPS MATCH THIS O-RING?
Common pairings include 3973511 (’98.5–’02) and 4962608 (’94–’98). For other years, confirm by VIN/ESN.
| Specifications for CUMMINS 3973512 | |
|---|---|
| UPC | n/a |
| GTIN | n/a |
| Shipping Info | Calculated at checkout (small seal — ships easily USPS/UPS ground) |
| Cross Reference | Factory Cummins Engine Oil Cap O-Ring, P/N 3973512 |
| E-Codes | |
| Prop 65 Warning | |
