John Deere 4045 / 6068 — Testing Thermostats Opening Temperature
Testing & diagnosis · Cooling system
For the John Deere 4045 / 6068, from the John Deere operator's manual.
Applies to: John Deere 4045, John Deere 6068
Before you start
- DO NOT allow thermostat or thermometer to rest against side or bottom of container when heating water.
Procedure
- Remove radiator pressure cap and partially drain cooling system.
- Remove thermostat cover and check for cracks or damage.
- Remove all three thermostats from the housing.
- Remove and discard rubber seal from each thermostat.
- Suspend thermostat and a thermometer in a container of water.
- Stir water as it heats and observe opening action against specifications.
- Remove thermostat and observe smooth, slow closing action as it cools.
- Replace all three thermostats if any thermostat is defective.
Tools required
- Thermometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Thermostat start to open 82°C (180°F); fully open 94°C (202°F)
- Initial opening ranges and full open nominal values vary by thermostat rating
Full service-parts list: John Deere 4045 →, John Deere 6068 →
Source: John Deere 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.