Interstate-McBee M-3949688 CP3 Rectangular Ring Seal – 03–18 5.9L/6.7L Cummins

Direct-fit rectangular-profile ring seal for the CP3 fuel injection pump gear access cover on Cummins B-Series engines. This Interstate-McBee aftermarket replacement matches the OEM Cummins 3949688 specification for reliable, leak-free sealing on 2003–2018 5.9L & 6.7L applications.

• Purpose-built: Seals the CP3 gear access cover (Cummins cover P/N 4935281).
• OEM-style fit: Interchangeable with Cummins 3949688 for quick, hassle-free installs.
• Durable elastomer: Rectangular cross-section helps maintain sealing in the cover groove.
• Great value: Interstate-McBee quality at an aftermarket price point.

Specifications

Vehicle Fitment

Always verify by VIN/ESN for edge cases and build-date changes.

• Ram 2500/3500, 5.9L Cummins (CP3): 2003–2007
• Ram 2500/3500, 6.7L Cummins (CP3): 2007.5–2018
• Ram 4500/5500, 6.7L Cummins (CP3): 2008–2018
• Not for CP4-equipped systems (certain later 2019–2020 models).

Install Notes

• Clean the cover and housing groove; remove all old material and debris.
• Lightly lubricate the seal with clean engine oil before installation.
• Install cover and tighten fasteners to factory torque using the Cummins service manual.

Warranty

Interstate-McBee new engine parts typically carry up to 24 months coverage; fuel-injection items are generally 12 months. Coverage for this seal follows manufacturer policy; contact us if you need specifics for your application.

Why Buy From CPP Diesel

• ESN-verified fitment support from real diesel techs.
• Fast shipping and easy returns.
• One-stop shop for CP3 service parts, covers, bolts, and related seals.

FAQ