MBE 4000 DDEC VI Troubleshooting – Section 14.6 Inoperative Thermo-Modulated Fan

Section 14.6
Inoperative Thermo-Modulated Fan

To determine if an inoperative thermo-modulated fan is causing high engine coolant temperature, test the thermo-modulated fan. Refer to OEM guidelines.‪

1. If the thermo-modulated fan is functioning correctly, check thermostats; refer to "14.7 Faulty Thermostats" .
2. If the thermo-modulated fan is not functioning correctly, refer to "14.6.1 Thermo-Modulated Fan Replacement" .

Section 14.6.1
Thermo-Modulated Fan Replacement

Perform the following steps to replace inoperative thermo-modulated fan:‪

1. Replace inoperative thermo-modulated fan; refer to OEM guidelines.
2. Verify thermo-modulated fan replacement; refer to "14.6.1.1 Test Engine with Replaced Thermo-Modulated Fan" .

Section 14.6.1.1
Test Engine with Replaced Thermo-Modulated Fan

Perform the following steps to determine if thermo-modulated fan replacement resolved high engine coolant temperature:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

1. Start and run the engine.
2. Run the engine through its operating range with no-load for approximately five minutes, allowing the engine coolant to reach normal operating range.
   1. If the engine coolant temperature is 82-105°C (180-221°F), no further troubleshooting is required. Shut down the engine.
   2. If the engine coolant temperature is not 82-105°C (180-221°F), shut down the engine. Check thermostats; refer to "14.7 Faulty Thermostats" .