Car air-conditioning leak detection

Here you will find useful information and handy tips relating to leak detection in automotive air-conditioning systems.

A lack of refrigerant not only reduces the cooling performance of the air-conditioning system - it also damages the components. On this page you can find out which methods are efficient for detecting leaks in the refrigerant circuit. You will also find practical tips for the cost-effective and professional repair of faulty hoses and pipes in the air-conditioning system.

Important safety note The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their work. The information provided on this website is intended for use by suitably qualified personnel only.

 

AIR CONDITIONING LEAK IN CAR: DETECTION IN AC SYSTEMS: OVERVIEW

One of the most frequent causes of functional problems in the air-conditioning system are leaks in the refrigerant circuit. These lead to an unnoticed drop in filling level and thus to a reduction in performance or even complete failure. As far as refrigerant R134a is concerned in particular, it is well known that it diffuses out of rubber pipes and connections. Since air conditioning experts cannot be sure whether there is a leak or whether the refrigerant loss is the normal loss over time, careful leak detection is a must.

 

The following are tested:

  • All connections and lines
  • Compressor
  • Condenser and evaporator
  • Filter dryer
  • Pressure switch
  • Service connections
  • Expansion valve

 

Three leak detection methods are recommended:

  1. Contrast agent and UV lamp
  2. Electronic leak detection
  3. Leak detection with forming gas

Leak detection with contrast agent

CONTRAST AGENT

The contrast agent is added to the refrigerant in a number of ways (e. g. Spotgun contrast agent, dye cartridges etc.).

 

SPOTGUN/PRO-SHOT

The exact amount of contrast agent is injected using the Spotgun cartridge gun or the Pro-Shot system. Further advantage: Contrast agent can be added when the system is full.

 

LEAK DETECTION LAMPS

Escaping contrast agent is made visible by the UV light, thus localizing the leak.

Leak detection with electronic tester/with nitrogen/through foam generation

ELECTRONIC LEAK DETECTION USING A LEAK DETECTOR

Indicates leaks via acoustic signal. It detects halogen gases and uncovers even the tiniest of leaks at points that are difficult to reach (e.g. evaporator leaks).

 

LEAK DETECTION USING A NITROGEN SET

In addition to its function for drying the system, this tool can also be used for leak tests. For leak tests, a filling adapter is required for the service connection as well as a tube adapter. The emptied air-conditioning system is filled with nitrogen (maximum 12 bar). The system is then monitored for a period (e.g. 5–10 min) to see whether the pressure remains constant. The leak can be detected through a "hissing" noise. Otherwise, it may be sensible to make the leakage spot visible using leak detection agent. The leak detection agent is sprayed on from outside. It forms foam at the point of the leak. This method can only be used to detect larger leaks at easily accessible locations.

 

LEAK DETECTION USING A FORMING GAS LEAK INDICATOR

To detect leaks, the empty air-conditioning system is filled with forming gas, a mixture of 95% nitrogen and 5% hydrogen. The components are checked for leaks using a special electronic leak indicator. Due to the fact that hydrogen is lighter than air, the sensor needs to be moved slowly above the suspected leak (electrical connections/components). After the end of the leak detection, the forming gas can be released into the ambient air. This leak detection method complies with Article 6, §3 of the EU Directive 2006/40/EC.

CAR AIR CONDITIONING LEAK DETECTION WITH FORMING GAS: VIDEO

AC leak detection with forming gas

Detecting a leak in the air-conditioning system using forming gas.

 

01:39 min

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