Cummins/Onan — Replacing the Thermostat
Maintenance · Coolant thermostat
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
- Hot coolant is under pressure and can cause severe burns; let engine cool before loosening cap
Procedure
- Disconnect negative battery cable, let engine cool, remove access doors.
- Remove the coolant pressure cap.
- Remove two thermostat housing bolts and pull off housing, thermostat and gasket.
- Clean gasket area and install new thermostat and gasket.
- Apply Three Bond 1215 liquid sealant to top side of gasket.
- Replenish lost coolant, secure cap and doors, reconnect battery cables (negative last).
Tools required
- Wrenches Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Three Bond 1215 liquid sealant or equivalent
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.