Cummins/Onan — Test Thermostat
Maintenance
From a Cummins/Onan service manual covering: V12 Series, V6-140, V6-200, V6-VAL, V6-VIM, V8-185, V8-265, V8-350, V8-VALE, V8-VINE, VT12, VT8-430. Check it applies to your exact model before use.
Applies to: Cummins/Onan V12 Series
Before you start
- Reversing lip of seal will permit leakage.
Procedure
- Immerse thermostat in water with a thermometer.
- Heat water and observe opening and closing of thermostat against thermometer.
- Check stamping on thermostat; install same range new thermostat as that removed.
Tools required
- Thermometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- High 170/185°F; low 160/175°F; higher range 180/195°F
Full service-parts list: Cummins/Onan V12 Series →
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.