Series 50 – Section 27.6 Inoperative Thermo-Modulated Fan

Section 27.6
Inoperative Thermo-Modulated Fan

To determine if an inoperative thermo-modulated fan is causing high engine coolant temperature, perform the following:‪

1. Test the thermo-modulated fan; refer to OEM guidelines.
   1. If the thermo-modulated fan is functioning correctly, check thermostats; refer to "27.7 Faulty Thermostats" .
   2. If the thermo-modulated fan is not functioning correctly; refer to "27.6.1 Thermo-Modulated Fan Replacement" .

Section 27.6.1
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 "27.6.1.1 Test Engine with Replaced Thermo-Modulated Fan" .

Section 27.6.1.1
Test Engine with Replaced Thermo-Modulated Fan

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

1. Start and run the engine.
2. Run the engine through its operating range with no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
   1. If the engine coolant temperature is 88-96°C (190-210°F), no further troubleshooting is required. Shut the engine down.
   2. If the engine coolant temperature is not 88-96°C (190-210°F), shut the engine down. Check thermostats; refer to "27.7 Faulty Thermostats" .