CO₂ Leak Tester for Cylinder Heads and Cylinder Head Gaskets

Frequently Asked Questions About CO₂ Leak Testers for Cylinder Heads and Cylinder Head Gaskets

A CO₂ leak tester aids in diagnosis when there is suspicion that combustion or exhaust gases are entering the cooling system. Such gases can enter the cooling system, for example, through a damaged cylinder head gasket, cracks in the cylinder head, or damage to the engine block. Here, we answer common questions about CO₂ testing of the cooling system.

• What does a CO₂ leak detector check in the cooling system?

  A CO₂ leak tester checks whether carbon dioxide or combustion gases are present in the gas chamber of the engine cooling system.
   

  An elevated CO₂ level may indicate a connection between the combustion chamber or exhaust system and the cooling system. Possible causes include a damaged cylinder head gasket, a cracked cylinder head, or damage to the engine block.
   

  For this reason, the CO₂ test is often referred to as a cylinder head gasket test or a combustion gas test.

• When is it a good idea to perform a CO₂ test on the cooling system?

  A CO₂ test is particularly useful when symptoms indicate a possible connection between the combustion chamber and the cooling system.

  These may include, for example:

  • repeated coolant loss without any visible external leaks,
  • unusual pressure buildup in the cooling system,
  • air or gas bubbles in the expansion tank,
  • overheating problems,
  • unclear results from a standard cooling system pressure test.

  The test should always be considered part of a comprehensive engine diagnosis.

• How does a CO₂ leak detector with a reaction fluid work?

  In a chemical CO₂ leak test, gas from the cooling system is drawn through a special reaction fluid.

  If the drawn-in gas sample contains CO₂ from combustion gases, the fluid reacts and changes color. In Leitenberger testers, the gas is drawn through the test chambers using a rubber ball.
  
  Depending on the model, the tester is connected to the vehicle via a compatible cooling system adapter, a universal adapter, or a rubber cone.

• What does the color change in the CO₂ reaction liquid mean?

  With Leitenberger CO₂ leak detectors, the reaction fluid starts out blue.

  When exposed to combustion gases from a gasoline engine, the fluid may change color from blue to yellow. With diesel engines, the color changes from blue to green.

  The color change may occur gradually. Therefore, the test must be conducted and evaluated in accordance with the operating instructions.

• Why do professional CO₂ leak detectors have two test chambers?

  A two-chamber design increases the reliability of the chemical test. The drawn-in gas sample is passed sequentially through two chambers containing reaction liquid.

  This allows for better observation of the reaction and reduces the likelihood of misinterpretation.

  The Leitenberger LT 200.2, for example, uses this two-chamber technology and can be connected via a quick-connect coupling to compatible K, KS, or UA cooling system adapters.

• What is the difference between a chemical CO₂ leak detector and a digital CO₂ leak detector?

  A chemical CO₂ leak detector detects combustion gases through a color change in a reaction liquid. The method is simple and allows for an immediately visible assessment.

  A digital CO₂ leak detector, on the other hand, measures the CO₂ concentration using a sensor and displays a reading. This allows changes in concentration to be tracked and documented numerically.

  For example, the digital Leitenberger VGD 01 measures CO₂ concentrations up to 5,000 ppm and records minimum and maximum values during the measurement.

  Which method is more suitable depends, among other things, on the frequency of testing, the desired level of documentation, and workshop procedures.

• Does a positive CO₂ test conclusively indicate a faulty cylinder head gasket?

  No. An elevated CO₂ level in the cooling system initially indicates that combustion gases or exhaust gases are entering the cooling circuit.

  The cause may be a defective cylinder head gasket. However, other possible causes include a damaged or cracked cylinder head, damage to the engine block, or another connection between the combustion or exhaust side and the cooling system.

  To determine the exact cause, further tests may therefore be necessary, such as a compression test or engine pressure loss test.

• What is the difference between a CO₂ test and bleeding the cooling system?

  In a standard pressure test, the cooling system is subjected to controlled overpressure using a cooling system tester. This allows leaks to be detected if the pressure drops or coolant escapes.

  The CO₂ test addresses a different issue: it checks whether combustion gases are entering the cooling system.

  The two methods are therefore complementary. For example, a cooling system may appear leak-tight from the outside but still have an internal connection between the combustion chamber and the cooling circuit.

• What adapter is needed for a CO₂ leak tester?

  The required adapter depends on the tester model and the cooling system opening.

  For example, the Leitenberger LT 200.2 can be connected via its quick-connect coupling to compatible cooling system adapters from the K, KS, or UA series.

  Alternatively, CO₂ leak testers with rubber cones are available, which can be used more universally on suitable radiator or expansion tank openings.

• What CO₂ readings should raise a red flag when using a digital tester?

  For the Leitenberger VGD 01 digital sensor, a series of measurement tests and empirical data have determined values of approximately 150 to 300 ppm for intact internal combustion engines and values starting at about 600 ppm for defective engines.

  However, these values are not universally applicable limits for every vehicle. The exact assessment must be based on the specifications of the engine, vehicle, or system manufacturer, as well as the specific test conditions.

  This is precisely why, in addition to the absolute measured value, the trend in CO₂ concentration during the test is also relevant.