Cummins/Onan B48 — Oil Change
Maintenance · Oil System
For the Cummins/Onan B48, from the Cummins/Onan service manual.
Applies to: Cummins/Onan B48, Cummins/Onan B48M engine
Before you start
- Hot crankcase oil can cause burns
- Change oil more frequently under dusty, high ambient, or low ambient conditions
Parts for this job
Part numbers from the service-parts list for Cummins/Onan B48. Verify against your serial number before ordering; some links are affiliate links.
Procedure
- Change crankcase oil after first 25 hours of operation
- Change every 100 hours thereafter
- Run engine until thoroughly warm before draining
- Stop engine and place pan under drain outlet
- Remove oil drain plug or open drain valve
- Allow oil to drain completely
- Replace drain plug or close drain valve
- Refill with oil of correct API classification and appropriate SAE viscosity
- Start engine and run briefly to check for oil leaks
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Oil capacity: 2.84 L without filter, 3.1 L with filter
- Change interval: 25 hours initial, then every 100 hours
Full service-parts list: Cummins/Onan B48 →
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.