121321 Cummins O-Ring
Used In These Kits
This part is included in 10 engine & overhaul kits — find yours below.
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121438Cummins ISX SERIES FUEL PUMP SERVICE KIT In stock -
131253Cummins TURBO MOUNTING GASKET KIT In stock -
131254Cummins ISB ENGINES LOWER GASKET KIT In stock - 131685LOWER GASKET KIT View ›
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131739Cummins QSB SERIES ENGINE LOWER GASKET KIT In stock -
131799LOWER GASKET KIT In stock -
131830Cummins QSB SERIES ENGINE LOWER GASKET SET In stock -
131865Cummins LOWER GASKET KIT In stock -
141440Cummins EGR COOLER INSTALLATION KIT In stock -
680354Detroit Fuel Pump In stock - No kits match that search.
Suggested Additional Parts
Commonly sold with this product. These parts are sold separately.
| Brand | PAI Industries |
| Part Category | Seals & O-Rings |
| Sub-Type | O-Ring |
| Engine Make | Cummins |
| Condition | New |
| Stage / Tier | Standard |
Cataloged cross-reference numbers for this product. Confirm fitment before ordering.
| Number |
|---|
| 3679139 |
| 3949781 |
| 4333-1837803C91 |
| 1837803 |
| 1837803C1 |
No cross-reference numbers match that search.
Discovery models are listed below. Confirm the complete application and any ESN/CPL or size restrictions before ordering.
Most PAI parts carry a 2-year unlimited-mileage PAI warranty — 3 years on the High Performance tier, 1 year on Excel by PAI. See Warranty & Returns for full coverage terms, or call a specialist to confirm the exact coverage on this part.
PAI published warranty tiers: High Performance — 3-Year · Genuine PAI — 2-Year · Excel — 1-Year, unlimited mileage. The badge beside the price shows this product's recorded term; when no badge is shown, confirm coverage with a specialist.