Section 14.7 Faulty Thermostats

Section 14.7
Faulty Thermostats

To determine if faulty thermostats are causing high engine coolant temperature, perform the following:‪

  1. Remove thermostat from the thermostat housing, refer to MBE 4000 Service Manual (6SE420), Chapter 4”Cooling System — Thermostat”.
  2. Inspect thermostat for correct operation, refer to MBE 4000 Service Manual (6SE420), Chapter 4, “Cooling System — Thermostat”.
    1. If thermostat is fully open at 95°C (203°F), check coolant pump; refer to "14.8 Faulty Coolant Pump" .
    2. If thermostat is not fully open at 95°C (203°F), refer to "14.7.1 Thermostat Replacement" .

Section 14.7.1
Thermostat Replacement

Perform the following steps to replace thermostats:‪

  1. Install new thermostat, refer to MBE 4000 Service Manual (6SE420), Chapter 4, “Cooling System — Thermostat”.
  2. Verify replaced thermostat; refer to "14.7.1.1 Test Engine with New Thermostat" .
Section 14.7.1.1
Test Engine with New Thermostat

Perform the following steps to determine if thermostat replacement resolved high engine coolant temperature:‪

warning

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 coolant pump; refer to "14.8 Faulty Coolant Pump" .


EPA07 MBE 4000 DDEC VI Troubleshooting Guide - 6SE568
Generated on 10-13-2008

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