Kohler — Coolant Temperature Sensor Service Kit Installation (GM31990 and GM31991)
Maintenance
From a Kohler service manual covering: 125REOZJG, 150 REOZJ4, 150REZG, 175REOZT4, 2000REOZM, 2000REOZMD, 2250REOZDD, 275REOZJD, 275REOZJE, 400REZX, 400RZX, 48REOZK4…. Check it applies to your exact model before use.
Applies to: Kohler 125REOZJG, Kohler 150 REOZJ4, Kohler 150REZG, Kohler 175REOZT4, Kohler 2000REOZM, Kohler 2000REOZMD, Kohler 2250REOZDD, Kohler 275REOZJD, Kohler 275REOZJE, Kohler 400REZX, Kohler 400RZX, Kohler 48REOZK4
Before you start
- Failure to upgrade software after changing the coolant temperature sensor will cause the controller to sense a lower than actual coolant temperature.
Procedure
- Remove generator set from service; master switch OFF/RESET, disconnect battery charger and starting battery negative lead first.
- Locate and remove the coolant temperature sensor; drain coolant to just below sensor.
- Clean threaded hole in engine block and install new sensor (Loctite Vibra-Seal 516 already applied).
- Attach electrical connector to the coolant temperature sensor.
- Fill radiator with coolant per engine operation manual recommendation; deaerate air in cooling system.
- Place generator set into service; reconnect battery negative lead last and battery charger.
- Install the application software version 2.21 or higher as needed using Program Loader.
- Select the temperature sensor part number in Menu 20, Factory Setup and press YES and ENTER.
- Remove F2 fuse for 10 seconds and replace to reset the microprocessor.
- Start the generator set and verify engine water temperature reading is valid.
Tools required
- Personal computer Amazon
- Null modem RS-232 cable with 9-pin male plug Amazon
- Program Loader Software Amazon
- Application Code Software Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Kohler 125REOZJG →, Kohler 150 REOZJ4 →, Kohler 175REOZT4 →, Kohler 2000REOZM →, Kohler 2000REOZMD →, Kohler 2250REOZDD →, Kohler 275REOZJD →, Kohler 275REOZJE →, Kohler 48REOZK4 →
Source: Kohler 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.