Cummins/Onan — Changing Engine Oil and Filter
Maintenance
From a Cummins/Onan owner's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HDKA, Cummins/Onan HDKAH, Cummins/Onan HDKAJ, Cummins/Onan HDKAK
Before you start
- Keep oil level between FULL and ADD marks
- Too much oil causes high consumption
- Too little oil causes engine damage
Procedure
- Run engine until warm, then stop
- Remove oil fill cap and dipstick
- Place pan underneath and unscrew oil drain plug
- Let all oil drain completely
- Reinstall oil drain plug and tighten securely
- Squeeze access door latches and let door swing down
- Spin off oil filter canister
- Wipe filter mounting surface and remove old gasket
- Apply thin film of oil to new filter gasket
- Spin on new filter until gasket touches then turn 1/2 to 3/4 turn more
- Close access door securely
- Refill with 3 quarts of proper grade oil
- Check oil level and adjust as needed
- Reinsert dipstick and screw cap on securely
- Dispose of used oil and filter per environmental regulations
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Oil capacity: 3 quarts (2.6 L)
- Oil grade: Performance Class CH-4, CG-4 or CF-4
Full service-parts list: Cummins/Onan HDKA →, Cummins/Onan HDKAH →, Cummins/Onan HDKAJ →, Cummins/Onan HDKAK →
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.