Cummins/Onan — Replace Lubricating Oil Filter
Maintenance
From a Cummins/Onan owner's manual covering: 4B3.9, 4BT 3.9, 4BTA 3.9, 6B5.9, 6BT 5.9, 6BTA5.9, B3.9, B5.9, C8.3. Check it applies to your exact model before use.
Applies to: Cummins/Onan 4B3.9, Cummins/Onan 6BTA5.9, Cummins/Onan B5.9 engine
Before you start
- Mechanical overtightening of filter can distort the threads or damage the filter element seal.
Procedure
- Clean the area around the lubricating oil filter head.
- Remove the filter using a 90- to 95-mm filter wrench.
- Clean the gasket surface of the filter head; make sure the o-ring is removed.
- Fill the filter with clean lubricating oil before installation.
- Apply a light film of lubricating oil to the gasket sealing surface.
- Install the filter as specified by the filter manufacturer.
Tools required
- 90- to 95-mm filter wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Do not use a four-cylinder oil filter on a six-cylinder engine
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.