Product Description
Interstate-McBee M-4939587 High Volume Oil Pump — 89–02 5.9L Cummins (Aftermarket Replacement)
High-volume replacement oil pump for the 1989–2002 5.9L Cummins B-Series. Designed for reliable lubrication in stock and mildly modified engines, as well as higher-mileage applications. Sold individually.
- Increased flow: High-volume design helps maintain stable oil pressure across the RPM range.
- Direct replacement: Installs in the factory location with OE-style fit and function.
- Durable construction: Precision-machined internals for consistent performance.
- Service-friendly: Ideal during timing cover, cam, or bottom-end refreshes.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-4939587 |
| OEM Reference | Cummins 4939587 |
| Application | 5.9L Cummins B-Series (12-valve & 24-valve) |
| Model Years | 1989–2002 |
| Sold As | Each (1 oil pump) |
What’s Included
- (1) High volume oil pump, P/N M-4939587
Vehicle Fitment
Always verify by engine serial number (ESN) when possible.
- Dodge Ram 2500/3500 with 5.9L Cummins
- 1989–1998: 12-valve 6BT
- 1998.5–2002: 24-valve ISB
- Other B-Series applications where Cummins 4939587 is specified (confirm by ESN).
Recommended/Related Parts
- Oil pickup tube O-ring
- Timing cover/front cover gasket set
- Oil pan gasket & RTV
- Oil pressure sensor/switch (for accurate readings)
- Quality engine oil & filter for initial run-in
Install Notes
- Pre-lube/prime the pump before installation to prevent dry start.
- Inspect and replace the pickup tube O-ring; ensure the pickup is free of debris.
- Verify pressure relief/gear clearances per the Cummins service manual.
- Torque fasteners to spec and check oil pressure on first start.
Why Buy From CPP Diesel
- ESN-verified fitment help from diesel specialists
- Fast shipping, easy returns, competitive pricing
- Deep inventory of B-Series service parts
FAQ
Will this work on both 12-valve and 24-valve 5.9L Cummins?
Yes—this listing covers 1989–1998 12-valve and 1998.5–2002 24-valve applications. Verify by ESN for edge cases.
Do I need anything else to install?
We recommend a new pickup tube O-ring, fresh oil/filter, and any required timing/front cover gaskets or RTV.
Will a high-volume pump raise oil pressure?
It can help maintain pressure under load and at temperature, but final readings depend on overall engine condition and clearances.
