Cummins/Onan — Draining, Cleaning and Refilling the Cooling System
Maintenance · Engine cooling system
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKB, Kubota D1105 engine, Kubota V1305 engine, Kubota V1505 engine, Kubota V1903B engine, Kubota V2203B engine, Kubota V2803B engine, Kubota V3300-E2B engine
Before you start
- Hot coolant is under pressure and can cause severe burns.
- Filling a hot engine with cold water can cause cracks in the manifold, head and block.
Procedure
- Disconnect the negative cable at the battery and let the engine cool.
- Remove the pressure cap and open the block and heat exchanger drain valves.
- Drain the coolant into suitable containers for hazardous-waste disposal.
- Clean and flush the cooling system with radiator cleaning chemicals per manufacturer.
- Close the drain valves and fill through the engine fill neck to the bottom of the neck.
- Start and run the engine a couple of minutes, shut down and add coolant as needed.
- Refill the recovery tank up to the COLD mark.
Tools required
- Radiator cleaning chemicals Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Fill system to the bottom of the fill neck
- Refill recovery tank to the COLD mark
Full service-parts list: Cummins/Onan MDKB →, Kubota D1105 engine →, Kubota V1305 engine →, Kubota V1903B engine →, Kubota V3300-E2B engine →
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.