Skip to main content


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

  1. Remove thermostat from the thermostat housing; refer to Section .
  2. Inspect thermostat for correct operation; refer to Section .
    1. If thermostat did not open at 97C (207F), refer to section .

Thermostat Replacement

Perform the following steps to replace thermostats: ‪

  1. Install new thermostat; refer to Section .
  2. Verify replaced thermostat; refer to Section .
Test Engine with New Thermostat

Perform the following to determine if thermostat replacement resolved low 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 88-96C (190-210F), no further troubleshooting is required. Shut the engine down.
    2. If the engine coolant temperature is not 88-96C (190-210F), shut the engine down.. Contact DDC Technical Service.