Leakage of coolant from the A/C system of cars is a very common problem. Most of us ignore the cause and get the refrigerant refilled but we are not aware of its consequences. Leakage in the A/C permits the entry of moisture and air into the system. Moisture reacts with the coolant to form acids, which destroy the compressor. Secondly, the refrigerant is expensive and filling it up every time hurts the pocket a lot. Most importantly, the leaked refrigerant gradually reaches the stratosphere and damages the ozone layer. The main constituent of refrigerant is CFC which depletes Ozone. Hence, by not bothering about the leakage of refrigerant in our A/C systems, you bring harm to the environment.
Leakage of refrigerant
If the A/C in your car is not able to keep the temperatures under control as it used to do earlier, there might be a leakage of the refrigerant. Before thinking of spending money, you should inspect the system for small faults.
The most common method is observing and looking for oil stains around the assembly.
The places you need to check are
1) Compressor Assembly
The shaft, seal and Compressor together form an assembly. During the leakage of refrigerant, the oil contained inside will be thrown away from the rod, near the engine and nearby spots due to rotational motion of the assembly under strong centrifugal force. You need to check these spots for oil and filth. If you find any, this trace clearly indicates leakage of coolant from the compressor block. Now that you know the faulty region, you can go for diagnosis and get it fixed.
The evaporator has a drain hole to send out the entire residue called the condensate. If there is a leakage of the refrigerant from the A/C, there are chances of leakage of oil through this drain hole as well.
You need to touch and feel around this drain hole and if you find oil present over there, there is a problem with the evaporator and it needs to be fixed.
After the A/C has been turned off and the system has cooled down a bit, you can look for oil traces below all the connections. If oil is found, take steps to get the connections repaired.
Another method of tracing the leakage is adding some leak detecting dyes to the system and then observing the visible area for the coloured dye near the connecting pipes. But this method is not as efficient as dyes fail to show leaks in the evaporator and any other internal system.
The third method which is more efficient and used by professional technicians is using electronic leak detectors to find out the leakage. Electronic leak detectors depend upon system pressure for their working.
Depending on the temperature outside, the normal pressure at rest is between 60 to 95 PSI. This means that the pressure in the lower side is higher at rest than as compared to at the time of normal operation. Similarly the pressure on the higher side is low at rest. So, you must take care of the side (low or high) to test with the electronic leak detector when the system is operating and when the system is at rest.
When there is leakage of the coolant, it evaporates and gets dissolved into air. The electronic leak detector senses the refrigerant present in the air. These are very sensitive devices, due to which they are very efficient. They are able to sense even a small leakage like ¼ oz. of refrigerant leaking annually.