What Does the Oil Pump Do?
The oil pump circulates engine oil under pressure to:
- Lubricate moving parts (crankshaft, camshaft, pistons, etc.)
- Cool internal components by dissipating heat
- Clean the engine by carrying contaminants to the oil filter
- Maintain hydraulic pressure for systems like variable valve timing (in some models)
If the oil pump fails — even partially — it can lead to catastrophic engine failure.
Common Signs of a Failing Cummins Oil Pump
Knowing the symptoms of a worn or failing oil pump can help you avoid major repairs:
| Symptom | Potential Cause |
|---|---|
| Low oil pressure warning | Worn gears or relief valve failure |
| Increased engine temperature | Insufficient oil circulation |
| Ticking or knocking noise | Lack of lubrication in valvetrain or crankshaft |
| Metal shavings in oil | Internal component wear due to poor lubrication |
If you experience any of these symptoms, it’s time to inspect or replace the oil pump immediately.
Choosing the Right Oil Pump for Your Cummins
Not all oil pumps are created equal. When selecting a replacement, consider:
- Compatibility: Ensure it fits your engine model (5.9L 12v/24v, 6.7L, ISX, etc.)
- Material quality: Hardened gears and reinforced housings last longer
- Oil flow rate: Performance builds may require high-volume pumps
- Brand reputation: Stick with trusted manufacturers for long-term reliability
Pro Tip: Upgrade While You're In There
If you're already doing a bottom-end rebuild or oil pan job, upgrading to a high-volume or performance oil pump can be a smart move — especially for tuned or high-mileage Cummins engines. Some aftermarket pumps also improve oil flow to known weak spots like cam bearings or lifters.
Final Thoughts
The oil pump may not be the most glamorous part of your Cummins build, but it’s arguably one of the most important. Whether you're maintaining a daily driver, building a towing monster, or racing the strip, reliable oil flow means reliable power.