Cooling System Leak Testing (CO2 Testing)
This procedure should be used to localize exhaust gas relevant cooling leakages and cooling fluid in the combustion chambers.
Check the cooling system for proper coolant fluid level. The coolant level in the radiator surge tank should match the MAX level marking (1). Correct the coolant level if necessary.
- Carefully open the radiator surge tank cap one turn by another and release the pressure.
Install a carbon dioxide tester (1) filled with indicator fluid to the radiator surge tank.
- To ensure the functionality of the indicator fluid, the following test can be performed:
- Remove the filled indicator fluid chamber of the carbon dioxide tester
- Blow some breathing air to chamber and the fluid
- The blue indicator fluid must change the color to yellow, otherwise replace with new fluid
- Start the engine and allow it to run for some minutes at idle speed.
- Aspirate air from the radiator surge tank to the carbon dioxide tester (1). Thereby take care, that no coolant fluid enters the tester.
- If the indicator fluid in the upper chamber of the tester changes its color to yellow, the occurrence of coolant fluid in the combustion chamber is indicated.
- Stop the engine.
- Coolant in the combustion chamber could be caused by the following reasons:
- Damaged cylinder head
- Damaged cylinder head gasket
- Damaged engine block
- Defect in the exhaust gas recirculation system
- Remove the carbon dioxide tester and install the radiator surge tank cap.
Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap. Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.
The engine should have a cooling fluid temperature of 80°C (176 °F).
The blue indicator fluid will react with a minimum concentration of carbon dioxide and changes the color to yellow then.