Cummins/Onan JWC4-10S-3 — Inspecting and Changing Crankcase Oil and Oil Filter Element
Maintenance · crankcase / oil filter
For the Cummins/Onan JWC4-10S-3, from the Cummins/Onan service manual.
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Procedure
- Lift out bayonet oil gauge and examine oil; if dark, install new oil filter element.
- Drain oil while engine is warm; close drain valve securely.
- Refill crankcase to FULL mark with clean fresh oil of proper grade.
- To replace element: remove filter cover and drain plug, drain filter.
- Remove and discard old element; clean sludge and sediment from filter body.
- Replace drain plug, install new element and cover with new gasket.
- Start engine, check for leaks; after 10 minutes stop and check oil level, add if necessary.
Tools required
- Oil filter wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Crankcase capacity approximately 4 quarts
- Fill to FULL mark on bayonet gauge
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.