Cummins/Onan B43 / B48 — Oil Change
Maintenance · Crankcase
For the Cummins/Onan B43 / B48, from the Cummins/Onan owner's manual.
Applies to: Cummins/Onan B48, Cummins/Onan B43M engine, Cummins/Onan B48M engine
Before you start
- Hot crankcase oil can cause burns; wear protective clothing and keep fingers and hands clear when draining oil.
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
- Run engine until thoroughly warm before draining oil, then stop the engine.
- Place a pan under the drain outlet and remove the oil drain plug or open the drain valve.
- After the oil is completely drained, replace the drain plug or close the drain valve.
- Refill with oil of the correct API classification and appropriate SAE viscosity grade.
- Oil level should be to the FULL mark of the dipstick.
- Start the engine and run briefly to check for oil leaks around the drain plug.
Tools required
- Drain pan Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- API SF, SF/CC, or SF/CD
- Crankcase capacity 1.7 qts (1.6 litre) without filter
Full service-parts list: Cummins/Onan B48 →
Source: Cummins/Onan owner's 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.