1991 Mercedes-Benz 420SEL Air Conditioning System Leak Inspection Cost

Diagnosis of the air conditioning system requires advanced knowledge of air conditioning systems, and a good understanding of the relationship between temperature and pressure of a liquid and gas. A technician with proper training, and certification is required to repair an air conditioning system. Professional grade equipment is used to read high and low side pressure, and the technician must rely on hours of classroom and hands-on training to understand the readings, diagnose the faulty part, and recommend a repair. If a leak is suspected, the technician may place an ultraviolet (UV) dye in the A/C system, and check for leaks with a UV flashlight. Using this method, the leak is very obvious, and the diagnosis is proven as soon as the UV dye is detected on or around an air conditioning component. A helpful sign for technicians when diagnosing air conditioner leaks is a hissing noise, or obvious damage to air conditioning components.

Replacement of most air conditioning components requires complete evacuation of the air conditioning system with a refrigerant recovery machine. Once components are re-installed, the technician will remove all air from the system in preparation for recharging the system with new refrigerant. Once any leaky seals have been replaced, or if the system has been verified to hold pressure, the technician will evacuate and recharge the system with new refrigerant and oil.

Refrigerant is environmentally harmful, and should never be released into the air. Instead, a proper refrigerant recovery machine must be used to protect the technician, and the environment. We do not recommend attempting to recharge the A/C system at home, as products available to consumers tend to contain substances that can cause damage to expensive refrigerant recovery equipment. Lastly, if your vehicle has not been converted from R12 to R134a refrigerant, the best time to have this service completed is when the air conditioning system is already being serviced.

Refrigerant is a dangerous chemical that can cause severe chemical burns to the skin and eyes if improperly handled, and discharging into the atmosphere will cause damage to the ozone. Refrigerant types are updated over time, and the appropriate type must be used. If there has been an update or conversion from an older refrigerant type, a label should be placed under the hood to make your technician aware of the change. Depending on location, it may be illegal for a technician to replace refrigerant without updating the A/C system to handle the newest type. Even if the air conditioner has a leak, the refrigerant may still be under pressure, and may cause injury if serviced improperly.

The air conditioning system is not serviceable without proper recovery and evacuation equipment, and attempting to release refrigerant into the air can result in severe chemical burns. Recharging the A/C system should be left to certified professionals, and is not considered a DIY job.