Air conditioning needs 'only' gas recharge? Solution is not that simple
Those looking for a used, but well-equipped car, are sometimes faced with the following words in classified ads: “the air conditioner works, you just need a gas refill”. Since such a problem is apparently simple to solve, the deal may seem tempting if, at the most, the vehicle is in order. But that's not quite the case: the device probably needs a much more complex (and expensive) service than the one advertised by the seller. For more references, check out: Does your AC system need an oil refill?
It turns out that the gas that makes the air conditioner work circulates in a sealed circuit and, therefore, remains constant: the need for recharging is a clear sign of leakage.
The most common refrigerant gas in automotive air conditioning systems is type R134a, harmless to the ozone layer. When circulating through coils and heat exchangers, it absorbs the high temperatures of the cabin.
Metallurgical engineer and master of materials Marco Colosio, director of SAE Brasil, explains that the automotive air conditioning system is filled with a volume of gas charge specified by the manufacturer. “When (a gas leak) is detected, it is a damaged sealing component”, he summarizes.
What makes salespeople minimize the defect is that even when there is a shortage of gas in the system, the air conditioning compressor can continue to function, but without cooling efficiency.
In such cases, replacing the refrigerant element even makes the appliance work; however, only for a short time. After a few days, the substance will have escaped completely. Consequently, the equipment again becomes unable to air condition the vehicle.
Gas refill need may require complex air conditioning service
The difficulty in stopping a gas leak in the air conditioner stems from the complexity of the system. It is because there are several points sensitive to damage: “there may be leaks in the seals of the rubber rings and in the condenser, in the evaporator hoses or in weld joints with process defects”, explains Colosio.
According to the engineer, defective material, lack of periodic maintenance or simply the time of use of the device are common causes of wear.
And don't stop there: the SAE specialist points out other possible causes of defects in the air conditioning unit. “There can also be failures in the hot air valve, in the radiator thermostatic valves, in the hot air radiator and in the hot air valve drive cables”, he warns.
To diagnose the problem, it is necessary to use an air recycling machine and also an ultra-violet lamp, able to locate the added contrast next to the gas charge. Adequate technical assistance, with specific equipment and specialized labor, represents a cost to the consumer.
Repair may include changing parts and disassembling components. Thus, the value varies widely depending on the car model and the location where the gas is leaking.