Product Description
Interstate-McBee M-3900267 Tappet Cover Bolt Seal – 89–98 5.9L Cummins 12-Valve
OE-style sealing washer for the tappet (lifter) cover bolts on the 1989–1998 Dodge Ram 2500/3500 with the 5.9L Cummins 12-valve (6BT). Replacing aged or flattened seals helps stop oil seepage around the bolt heads and restores a clean, dry engine exterior. Sold individually.
- Direct replacement: Matches OE form and function for a reliable seal at each tappet cover bolt.
- Leak prevention: Fresh seals cure seepage caused by hardened or crushed originals.
- Service friendly: Simple install during tappet cover or gasket service.
- Value: Interstate-McBee quality at an aftermarket price.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-3900267 |
| OEM Reference | Cummins 3900267 |
| Location | Tappet (lifter) cover bolt seal |
| Sold As | Each (1 seal) |
| Quantity Required | One per tappet cover bolt (count your bolts and order accordingly) |
What’s Included
- (1) Tappet cover bolt seal, P/N M-3900267
Vehicle Fitment
Always verify by engine serial number (ESN) when possible.
- Dodge Ram 2500/3500 5.9L Cummins (12-valve 6BT)
- Model Years: 1989–1998
- Additional Cummins B-Series applications where 3900267 is specified (confirm by ESN).
Recommended/Related Parts
- Tappet cover gasket (replace whenever the cover is removed)
- Tappet cover bolts/hardware (inspect for corrosion or damaged heads)
- Brake cleaner and lint-free wipes for surface prep
Install Notes
- Clean the bolt head seats and tappet cover area thoroughly before installation.
- Install one new seal per bolt; do not reuse crushed or hardened seals.
- Torque tappet cover bolts to the specification in the Cummins service manual.
- Do not overtighten—overtorque can deform seals and the cover.
FAQ
How many seals do I need?
Order one seal for each tappet cover bolt. Count the bolts on your engine to determine the quantity and consider adding a couple of extras.
Can I reuse the old seals?
Reusing old seals isn’t recommended. They harden and compress over time, which leads to oil seepage.
Does this fit 24-valve (1998.5–2002) engines?
This listing is for the 12-valve 5.9L Cummins. For 24-valve engines, check the correct part number before ordering.
