Cummins/Onan B48 — Oil Filter 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
- Do not overtighten filter gasket
- Do not use pipe wrench or oil filter strap wrench that may damage element
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
- Replace oil filter after first 25 hours of operation
- Replace every 100 hours thereafter
- Spin off oil filter element and discard
- Thoroughly clean filter mounting surface
- Install new element ensuring new gasket is in element
- Apply thin film of oil to gasket
- Spin element by hand until gasket just touches mounting pad
- Turn down additional 1/4 to 1/2 turn
- Do not overtighten
- Start engine and check for leaks around filter element
Tools required
- Oil filter wrench (if needed) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Replace 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.