Cummins/Onan — Draining and Cleaning Cooling System
Maintenance
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HDKC
Before you start
- Hot coolant spray can cause severe burns
- Ethylene glycol antifreeze is considered toxic; dispose according to local regulations
Procedure
- Let the engine cool before removing the pressure cap.
- Relieve any remaining pressure by turning the cap slowly, without pushing down.
- When the pressure has been relieved, push down on the cap and turn it the rest of the way to withdraw it.
- Remove the coolant drain plug and drain the coolant into a suitable container.
- Flush and clean the cooling system before refilling; follow cleaning and flushing instructions on the product.
Specs & values
- Coolant drain plug is 1/4 in Hex Socket
Full service-parts list: Cummins/Onan HDKC →
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.