Cummins/Onan — Changing Coolant (Drain and Fill)
Maintenance · Engine cooling system
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKAV, Cummins/Onan MDKAW, Cummins/Onan MDKAZ, Cummins/Onan MDKB, Kubota D1105 engine, Kubota V1305 engine, Kubota V1505 engine, Kubota V1903B engine, Kubota V2203B engine, Kubota V2803B engine
Before you start
- Ethylene glycol antifreeze is toxic; dispose of per local regulations
- Filling a hot engine with cold water can crack manifold, head and block
Procedure
- Disconnect negative battery cable, let engine cool, remove access doors.
- Remove the coolant pressure cap.
- Open block and heat exchanger drain cocks and collect used coolant.
- Clean and flush system with radiator cleaning chemicals if required.
- Close drain cocks and fill through engine fill neck to bottom of neck.
- Run engine a couple of minutes to dislodge air, shut down, top up.
- Secure pressure cap and refill recovery tank to COLD mark.
Tools required
- Towels and containers Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Fill to bottom of fill neck; recovery tank to COLD mark
Full service-parts list: Cummins/Onan MDKAV →, Cummins/Onan MDKAW →, Cummins/Onan MDKAZ →, Cummins/Onan MDKB →, Kubota D1105 engine →, Kubota V1305 engine →, Kubota V1903B engine →
Source: Cummins/Onan service 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.