CUMMINS 3913994 OEM TIMING PIN O-RING – 5.9L 12-VALVE (1989–1998)

Product Description

The Cummins 3913994 OEM Timing Pin O-Ring is the factory-correct seal that installs on the timing pin used for top dead center (TDC) alignment on all 1989–1998 5.9L 12-Valve Cummins 6BT engines. This genuine Cummins O-ring prevents oil seepage around the timing pin bore, ensuring a clean and accurate service reference point for pump timing and front cover work. If you’re replacing your timing pin or servicing the front gear housing, this OEM-grade O-ring is the only seal that guarantees proper fitment and long-term durability.

Fitment

• 1989–1998 Dodge Ram 2500/3500 with 5.9L 12-Valve Cummins (6BT)
• All 5.9L 12V B-series engines using a mechanical TDC timing pin

Cross-Reference (Cummins-Only)

Pair this O-ring with other timing-service components:

• CUMMINS 3903924 OEM TIMING PIN – 5.9L 12-VALVE
• CUMMINS 3900267 OEM TAPPET COVER BOLT GROMMET SEAL – 5.9L
• CUMMINS 3900625 OEM HEX FLANGE HEAD CAP SCREW – INTAKE AIR HEATER HARNESS BOLT

FAQ

Does the 3913994 O-ring fit all 12-valve Cummins timing pins?

Yes. This O-ring is the correct factory seal for all 1989–1998 5.9L 12V Cummins 6BT timing pins, including OEM replacement pin 3903924.

Should I replace the O-ring when installing a new timing pin?

Yes. The original O-ring often hardens with age and heat. Replacing it with a genuine Cummins 3913994 ensures a proper oil-tight seal.

Can I reuse my old timing pin O-ring?

No. Reuse can lead to leaks and inaccurate TDC checks. Always install a new O-ring during timing pin service.

Does this help with injection pump timing?

Yes. The timing pin is used to locate top dead center. A properly sealed pin bore helps maintain clean, reliable timing procedures.

Specifications for cummins 3913994