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To determine if combustion gases in coolant is causing high engine coolant temperature, perform the following: ‪

  1. Perform a cylinder compression test.
    1. If test results are to specifications; check radiator coolant flow, refer to section .
    2. If test results are not to specifications; refer to section .

Cylinder Head Gasket Replacement

Perform the following steps to replace cylinder head gasket: ‪

  1. Remove and replace cylinder head gasket; refer to section .
  2. Verify new cylinder head gasket replacement; refer to section .
Test Engine with Replaced Cylinder Head Gasket

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 88-96C (190-210F), no further troubleshooting is required. Shut down the engine.
    2. If the engine coolant temperature is not 88-96C (190-210F), shut down the engine. Check radiator coolant flow; refer to section .