Cummins/Onan — Draining and Refilling Cooling System
Maintenance
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HDKC, Cummins/Onan HDKCA, Cummins/Onan HDKCB
Before you start
- Hot coolant spray can cause severe burns
- Ethylene glycol antifreeze is toxic
Procedure
- Let engine cool, relieve pressure cap slowly then remove
- Remove coolant drain plug and drain coolant into a container
- Flush and clean cooling system before refilling
- Install drain plug with pipe thread sealant
- Fill system using funnel in fill hose to vent air, start and run genset a few minutes while venting
- Add coolant as necessary, secure pressure cap, fill recovery tank to COLD mark
Full service-parts list: Cummins/Onan HDKC →, Cummins/Onan HDKCA →, Cummins/Onan HDKCB →
Source: Cummins/Onan operator'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.