Cummins/Onan — Oil Seals
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Do not damage seal.
Procedure
- When replacing either crankshaft oil seal, ensure open side faces toward inside of engine.
- Do not turn back edge or damage seal.
- Rear bearing plate must be removed to replace rear oil seal.
- Remove gear cover to replace front oil seal.
- Clean sealing surfaces. Apply shellac or Permatex around seal.
- Install seal flush with outer edge of plate bore (rear) or gear cover.
Tools required
- seal driver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.