Product Description
Interstate-McBee M-5259499 Rear Oil Seal – 1989–2018 5.9L / 6.7L Cummins (Aftermarket Replacement)
Rear crankshaft oil seal for the 1989–2018 Cummins B-Series (5.9L and 6.7L). Built to OE form, fit, and function to stop leaks at the rear main area. Sold individually.
- Direct replacement: Matches the dimensions and sealing profile of the OE part.
- Reliable sealing: Interstate-McBee quality materials for long service life.
- Service friendly: Ideal for engine reseal jobs, clutch/transmission service, or rebuilds.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-5259499 |
| OEM Reference | Cummins 5259499 (rear crankshaft oil seal) |
| Position | Rear main (crankshaft flange) |
| Sold As | Each (1 seal) |
| Qty Required | 1 per engine |
What’s Included
- (1) Rear crankshaft oil seal, P/N M-5259499
Vehicle Fitment
Always verify by engine serial number (ESN) when possible.
- Dodge Ram 2500/3500 with Cummins B-Series:
- 5.9L 12-Valve: 1989–1998
- 5.9L 24-Valve: 1998.5–2002
- 5.9L Common Rail: 2003–2007
- 6.7L: 2007.5–2018
- Additional ISB / B-Series industrial and medium-duty applications where Cummins 5259499 is specified (confirm by ESN).
Recommended/Related Parts
- Rear main seal installer/alignment tool (as required by service procedure)
- Crankshaft flange gasket or sealant (if applicable to your timing cover/retainer design)
- Engine oil and filter (for post-repair service)
Install Notes
- Follow the Cummins service manual procedure for removal and installation.
- Use a proper installer/alignment tool to avoid lip damage and ensure concentric seating.
- Inspect crank flange and seal bore; clean thoroughly and check for grooves or damage.
- Lightly lubricate the seal lip if specified by the procedure; do not over-oil.
Why Buy From CPP Diesel
- ESN-verified fitment support from diesel specialists
- Fast shipping, easy returns, competitive pricing
- Deep inventory of complementary Cummins B-Series service parts
FAQ
Will this fit my 5.9L or 6.7L Cummins?
Yes—this listing covers most 1989–2018 B-Series applications that call for Cummins 5259499. For absolute confirmation, verify by ESN.
Do I need a special tool?
Using the correct installer/alignment tool is highly recommended to prevent leaks from misalignment or lip damage.
Is a wear sleeve included?
No; this listing is for the seal itself. If your crank flange is grooved, repair or sleeve as required by the service manual.
Should I add sealant?
Only if the Cummins procedure for your specific retainer/timing cover calls for it. Refer to the factory service manual.
