Case IH 1002 – Engine Control Unit (ECU): Engine Coolant Temperature Is Above Normal

The engine control system has detected the coolant temperature exceeding safe operating limits.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Maxxum series tractors
• Magnum series tractors
• Steiger series tractors
• Puma series tractors
• Optum series tractors
• JX series tractors
• MX series tractors

1. 1

   Verify actual temperature using an infrared thermometer on the coolant lines and compare to the dashboard gauge to determine if the engine is actually overheating or if the sensor is faulty

2. 2

   Inspect radiator fins and air-to-air coolers for blockages caused by dust, chaff, dirt, or insects

3. 3

   Check coolant level, look for visible leaks, and inspect for degraded or contaminated coolant

4. 4

   Inspect the cooling fan, check for slipping or worn fan belts, cracked blades, or a failing viscous fan clutch

5. 5

   Ensure the lower radiator hose is not collapsing under suction and test the radiator cap with a pressure tester

6. 6

   Inspect the water pump for coolant weeping from the drain hole, indicating early seal failure

1. 1

   Clear Blockages

   If the radiator is plugged, thoroughly clean the radiator and coolers from the inside out using compressed air or water. Cleaning from the back forward is critical to push debris out the way it came in.

2. 2

   Replace the Thermostat

   If the engine is genuinely overheating and airflow is good, the thermostat is likely stuck closed. Drain the coolant, remove the thermostat housing, replace the thermostat and gasket, and refill the system.

3. 3

   Replace the Coolant Temperature Sensor

   If the infrared thermometer shows the engine is running at a normal temperature (e.g., 180°F) but the gauge is spiking, the sensor has failed. Locate the sensor on the engine block/thermostat housing, remove it, install the new sensor, and clear the fault code.

4. 4

   Service the Water Pump or Fan Clutch

   If the water pump is weeping or the fan clutch fails to engage under load, replace the faulty component and install a new serpentine/drive belt.

5. 5

   Flush Coolant

   If the coolant is old or contaminated, flush the system and refill with the correct OEM-specified coolant mixture.