Series 50 – Section 27.9 Combustion Gases in Coolant

Section 27.9
Combustion Gases in Coolant

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

1. Perform a cylinder compression test; refer to "29.2 Cylinder Compression Test" .
   1. If test results are to specifications, listed in Table "Compression Pressures at Various Altitudes" ; check radiator coolant flow; refer to "27.10 Abnormal Radiator Coolant Flow" .
   2. If test results are not to specifications, listed in Table "Compression Pressures at Various Altitudes" ; refer to "27.9.1 Cylinder Head Gasket Replacement" .

Section 27.9.1
Cylinder Head Gasket Replacement

Perform the following steps to replace cylinder head gasket:‪

1. Remove and replace cylinder head gasket; refer to "1.2.2 Removal and Cleaning of Cylinder Head" .
2. Verify new cylinder head gasket replacement; refer to "27.9.1.1 Test Engine with Replaced Cylinder Head Gasket" .

Section 27.9.1.1
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 88-96°C (190-210°F), no further troubleshooting is required. Shut the engine down.
   2. If the engine coolant temperature is not 88-96°C (190-210°F), shut the engine down. Check radiator coolant flow; refer to "27.10 Abnormal Radiator Coolant Flow" .