Cummins/Onan — Filling Coolant
Maintenance · Engine cooling system
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDGDA, Cummins/Onan MDGDB
Before you start
- To prevent severe scalding, let the engine cool down before removing the coolant pressure cap; turn the cap slowly
- The sea water pump has a neoprene impeller that can disintegrate quickly if pump prime has been lost
Procedure
- If heat exchanger cooled, prime the sea water pump by disconnecting the pump outlet hose and pouring water into the pump outlet (Figure 4-2).
- Reconnect the hose and open the sea cock.
- Fill coolant until the expansion tank is approximately half full. Bleed air from any air vents while filling coolant.
- Run the engine while watching the coolant level in the expansion tank; add coolant as necessary so the expansion tank is full at normal operating temperature.
- Secure the pressure cap.
Specs & values
- 50-50 FridayParts $119.95 mixture of fresh water and ethylene glycol antifreeze
Full service-parts list: Cummins/Onan MDGDA →, Cummins/Onan MDGDB →
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.