Product Description
Interstate-McBee M-3957912 Valve Stem Seal – 1989–1998 5.9L Cummins 12-Valve
Direct-fit valve stem seal for the 5.9L Cummins 12-valve (6BT). Restores proper valve stem lubrication control to help minimize oil consumption and smoke. Sold individually.
- OE-style fit: Matches Cummins reference 3957912 for B-series applications.
- Reliable sealing: Helps prevent oil from entering the combustion chamber through the valve guides.
- Service-friendly: Ideal for top-end refreshes alongside valves, springs, retainers, and keepers.
- Value: Interstate-McBee quality engineered to OE form, fit, and function.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-3957912 |
| OEM Reference | Cummins 3957912 |
| Sold As | Each (1 valve stem seal) |
| Qty Required (12V) | 12 seals (one per valve) |
| Position | Valve train — valve stem/guide |
What’s Included
- (1) Valve stem seal, P/N M-3957912
Vehicle Fitment
For best results, verify by engine serial number (ESN).
- Dodge Ram 2500/3500 5.9L Cummins (12-valve 6BT)
- Model Years: 1989–1998
- Additional B-Series applications where Cummins 3957912 is specified (confirm by ESN).
Recommended/Related Parts
- Valve spring retainers and keepers/locks
- Intake and exhaust valve kits (12-valve)
- Valve springs and push rods
- Head gasket and upper gasket set (for top-end refresh)
Install Notes
- Use proper valve spring compressor tools and wear eye protection.
- Replace all seals during service; do not mix old and new on the same head.
- Lightly lubricate the valve stem and seal; confirm correct orientation and seating depth.
- Follow the Cummins service manual procedures and torque specs.
Why Buy From CPP Diesel
- ESN-verified fitment assistance from diesel specialists
- Fast shipping, easy returns, competitive pricing
- Deep 6BT parts inventory to complete your repair
FAQ
How many seals do I need?
The 12-valve 5.9L uses 12 valve stem seals (one per valve). This part is sold individually.
Will this fit my 24-valve (1998.5–2002) engine?
No. This listing is for the 12-valve engine only. For 24-valve applications, use the part specified for your ESN.
Do I need special tools?
A quality valve spring compressor and suitable seal installer or protective sleeve are recommended to avoid damaging the seals.
