Cummins/Onan — Adding Oil
Maintenance · Engine oil
From a Cummins/Onan service manual covering: C25 D6, C30 D6, C35 D6, C40 D6, C50 D6, C60 D6. Check it applies to your exact model before use.
Applies to: Cummins/Onan C25 D6, Cummins/Onan C30 D6, Cummins/Onan C35 D6, Cummins/Onan C40 D6, Cummins/Onan C50 D6, Cummins/Onan C60 D6, Cummins/Onan 4BT3.3 engine, Cummins/Onan 4BT3.3-G5 engine, Cummins/Onan 4BT3.3-G7 engine
Before you start
- Contact with hot engines can cause severe burns.
Procedure
- Ensure the oil fill cap area is clean.
- Add the appropriate amount of oil.
- Recheck the engine oil level.
- Clean up and dispose of any oil per local regulations.
Specs & values
- Recommended lube oil: 15W40 Amazon Amazon eBay $94.00 eBay $49.74
- Lube oil capacity: 8.35 qt (7.9 L)
Full service-parts list: Cummins/Onan C25 D6 →, Cummins/Onan C35 D6 →, Cummins/Onan C50 D6 →, Cummins/Onan C60 D6 →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.