Interstate-McBee M-3936876 Rectangular Ring Seal – Oil Fill (89–98 5.9L Cummins 12V)

Stop oil mist and seepage at the oil fill. The Interstate-McBee M-3936876 rectangular ring seal is an OEM-style replacement for Cummins 3936876, used on many 1989–1998 Dodge Ram 2500/3500 5.9L 12-valve engines. Commonly installed under the oil fill cap and at the filler tube joint, this fuel- and oil-resistant seal restores a tight, leak-free fit.

• Direct-fit replacement: Matches OEM Cummins 3936876 profile for proper sealing.
• Fixes common leak points: Under oil cap and at filler tube interface on 12-valve B-series.
• Aftermarket value: Interstate-McBee quality without the OEM price tag.
• Quick install: Simple drop-in during cap/tube service; no special tools required.

Specifications

What’s Included

• (1) Rectangular ring seal for oil fill (M-3936876)

Vehicle Fitment

Always verify with your engine serial number (ESN) for edge cases.

• Dodge Ram 2500/3500 – 5.9L Cummins 12-Valve (6BT)
  • Model Years: 1989–1998 (oil cap and filler tube locations)
• Industrial/Commercial B-Series: Common on 4BT 3.9L and 6BT 5.9L variants (verify by ESN)

Install Notes

• Clean the cap and tube grooves thoroughly; remove old seal and residue.
• Lightly oil the new seal; press fully into the rectangular groove.
• Inspect both the cap and tube joint—many trucks use this seal in two spots.

Warranty

Interstate-McBee engine sealing components are backed by manufacturer warranty (typically 12–24 months; contact us for exact coverage on this item).

Cross-Reference & Compatibility

Direct replacement for Cummins 3936876. Also referenced as FP-3936876 and 3902363 by some distributors.

Why Buy From CPP Diesel

• B-series experts with ESN-verified fitment support.
• Fast shipping and hassle-free returns.
• Real-world tech help for leak diagnosis and install tips.

FAQ