High Coolant Temperature
engine
Description
Diesel Engine mode only: high coolant temperature activates the alarm, and the unit shuts down; Shore Power is alarm only.
Activation Conditions
Not for Shore Power mode. If the system is in Diesel Engine Mode AND the coolant temperature sensor alarm is NOT active AND engine is running AND any of the following conditions occur when the engine is running and NO oil pressure failures present: ambient temp > 48.9°C coolant temp >= 116°C ambient temp < 48.9°C coolant temp >=110°C coolant temp between 110°C and 116°C for 5 minutes and ambient >= 48.9°C.
Unit Behavior
If the system is in Diesel Engine mode, REQUIRED SHUTDOWN If the system is in Shore Power mode and the alarm is active, Alarm Condition Only·
Reset Conditions
If the system is in Diesel Engine Mode AND Coolant temperature < 100°C OR Alarm Reset OR Cycle Power
Corrective Actions
1. Check Coolant Level Do not remove the cap from a hot coolant system. If the cap must be removed, do so very slowly in order to release the pressure without spray. a. Check coolant level in the tractor surge tank (integrated) or coolant tank (stand-alone) Level must be in the normal range. 2. Inspect Coolant Hoses and Connections. a. Inspect hoses from APU to truck engine (integrated) or radiator tank (stand-alone). Check for leaks or restrictions in the hoses. Verify that any shut-off valves are in the open position. b. Check Freeze Point Of Coolant - Use Coolant Tester to check concentration of anti-freeze mixture. Must be between 40% to 60% Ethylene Glycol to water mixture. 3. Check Airflow Through Radiator a. Inspect condenser and radiator. Ninety percent or more of the coil surface must be undamaged. Radiator coil must be clean. b. Check airflow (with unit running). Verify even airflow through the entire coil and no “dead” spots. 4. Check radiator fan rotation / operation. Air should flow into the APU enclosure and be directed out through the radiator. 5. Check Water Pump Belt - Check belt condition. Verify no Glazing, no Cracking, no Slipping. Replace belt if required. Refer to Section 8.6.15. 6. Check Engine Coolant Temperature Sensor Wiring a. Inspect harness and APU Module connector pins and terminals. (See wiring schematic Section 10.3). Verify no physical damage to harness and no damage or corrosion in connectors. b. Check voltage at the sensor connector with the microprocessor powered up. Voltage reading should be 2.5 ± 0.1 VDC. This verifies microprocessor output and wiring connections to sensor. 7. 7. Check Engine Cooling System a. Compare actual engine temperature to the CabinTech system values reading. Refer to Section 3.15. Temperature must be within ± 20°F (± 11.1°C). b. Test operation of thermostat. Must operate correctly. c. Check water pump operation. Verify no seepage at weep hole, bearings tight and quiet, and Impeller firmly attached to shaft. d. Check cooling system for scale, sludge, rust, etc. Coolant must be clean and clear with no foreign particles or substances in it. Flush and clean the coolant system as necessary. e. Check water pump bypass hose to thermostat housing for internal blockage. Must be clear and open.