Buick Regal: Pressure Cap Testing

Special Tools

GE-42401-A Radiator Cap and Surge Tank Test Adapter

For equivalent regional tools, refer to Special Tools.

WARNING: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

1. Remove the pressure cap.

2. Wash the pressure cap sealing surface with water.

3.

Use a commercial cooling system pressure adapter (1) and moisten the rubber with coolant fluid.

4.

Install the commercial adapter (1) to the GE-42401-1A adapter (2). Use a suitable underlay to be able to use enough force. Inspect the assembly for proper seat then.

5.

NOTE: Lubricate GE-42401-1A adapter and pressure cap O-rings with coolant.

The GE-42401-1A adapter and the pressure cap should have room temperature to operate properly.

Use commercial coolant pressure tester (4) along with the commercial adapter (3) and install to the GE-42401-1A adapter (2).

6. Install the assembly to the pressure cap (1) and apply pressure.

7. Test the pressure cap for the following conditions:

• Pressure release when the pressure tester exceeds the pressure rating of the pressure cap.
• Maintain the rated pressure for at least 10 seconds.

8. Note the rate of pressure loss.

9. Replace the pressure cap under the following conditions:

• The pressure cap does not release pressure which exceeds the rated pressure of the cap.
• The pressure cap does not hold the rated pressure.

COOLING SYSTEM LEAK TESTING (CO2 TESTING)

NOTE: This procedure should be used to localize exhaust gas relevant cooling leakages and cooling fluid in the combustion chambers.

1.

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.

WARNING: 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.

2. Carefully open the radiator surge tank cap one turn by another and release the pressure.

3.

Install a carbon dioxide tester (1) filled with indicator fluid to the radiator surge tank.

4. To ensure the functionality of the indicator fluid, the following test can be performed: 1. Remove the filled indicator fluid chamber of the carbon dioxide tester 2. Blow some breathing air to chamber and the fluid 3. The blue indicator fluid must change the color to yellow, otherwise replace with new fluid 5. Start the engine and allow it to run for some minutes at idle speed.

NOTE: The engine should have a cooling fluid temperature of 80ºC (176 ºF).

6. Aspirate air from the radiator surge tank to the carbon dioxide tester (1). Thereby take care, that no coolant fluid enters the tester.

NOTE: The blue indicator fluid will react with a minimum concentration of carbon dioxide and changes the color to yellow then.

7. 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.

8. Stop the engine.

9. 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

10. Remove the carbon dioxide tester and install the radiator surge tank cap.

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