(1) 在一些情况下，维修人员是不能够为车冷气进行冷媒添加的。这些情况如下：
第一，车冷气零件已经出现大量泄漏冷媒的情况。
常见出现这类情况的零件有 ：冷媒输送管（pipping) ，蒸发器（cooling coil），压缩机（compressor/pump)，冷凝器（condenser）。在这类情况下，大多数的解决方法就是更换一个新的零件。
第二，回路阻塞。
一旦冷媒回路阻塞，瓦斯不能畅通流动到各个零件，强行加入冷媒只会带来更糟的后果，例如输送管或冷媒蓄筒爆裂。常见的回路情况出现在：压缩机与冷凝器之间，冷凝器与冷媒蓄筒之间。在这类情况下，解决方法就是将阻塞物吹出，如果阻塞情况已经很严重了，就得将相关零件更换新的。
第三，压缩机操作不正常
压缩机就像我们的心脏，用气压将冷媒输送到各个零件。如果压缩机不能压缩出足够的压力（严重的不够力/弱），就算添加冷媒也无补于事。无奈之际，也只有换一个新的压缩机了。
(2) 此外，有些情况是不需要为车冷气添加冷媒的。一些常见的情况如下：
第一，冷凝器的风扇没操作正常。
如果风扇操作时有时无，那会影响车引擎的温度，使而提高，因此冷气也会变得不冷了。在这类情况下，解决方法就是更换风扇的发动机 （Fan Motor)。
第二，电路故障
例如：继电器（Relay) 或 保险丝（Fuse) 短路而导致零件无法操作。除此之外，电线断了也可导致零件没有电源而无法操作。
第三，蒸发器遭灰尘阻塞
在这情况下会感觉到风量很小，但是冷度还够，每当到了天气热时，就会感到冷气不够冷了。我们的建议是将蒸发器拆出并进行清洗，清洗后再将冷媒添加回去就行了。这也是其中一项不是单单添加冷媒就能解决的情况。
如果排除以上的可能性，大致上就是因为车冷气冷媒不足了才导致冷气不冷的原因。专家说：连接各零件的胶管1年有100-200g 的自然泄漏。依我们的经验，一两年添加一次冷媒还算是正常的 ，如果添加后不到六个月又发觉冷气又不冷了，那就表示有地方泄漏冷媒了。
Currently, there are two types of Air-conditional Gas, which is R12 and 134a. Few years ago, the scientists proved that the R12 gas is non-environmental friendly. It has cause harmful effect to our atmosphere so they come out with an alternative gas which call 134a. Now, the new model cars is using this type of gas for their air-conditional. Due to this, the price of these two types of gas is different. Normally, the car services center would charge RM30 for one top up of gas R12, and RM40 for one top up of gas 134a (depends on the car model and air-cond condition).
(1) In some condition, the mechanicians CANNOT top up gas for air-conditional system.
Firstly, there is a big leaking spot in the system
Spare parts that always having gas leaking problem is such as pipping, cooling coil/evaporator, compressor/pump, and condenser. When there is gas leaking problem, the solution for it would mostly be exchanging with a brand new spare parts.
Second, there is a blocking on the pathway in the system
When there is blocking in the pathway, the gas cannot recycle and reach to all the parts in the system. If continue pumping the gas into the air-cond, it would cause a bad effect such as burst in pipping and filter dryer. This problem is mostly happened between the pathway of compressor and condenser, and also between condenser and filter dryer. We would try to blow out the dirt that blocking the pathway at first. But if the condition is already been in the bad state, we would only to exchange the spare parts with new one.
Third, compressor is in weak condition
Compressor/pump is just like our heart, it pump the gas throughout the air-conditional system. If the compressor is weak, it cannot give out enough energy to pump the gas, thus the car air-cond would feel like not cold enough or taking long time to cold up the car. Under this problem, if the car owner really want their air-cond in a better condition, we would only advise them to exchange the compressor with a brand new one.
(2) Beside that, there are some conditions that NO NEED to top up gas for the air-conditional system.
Firstly, the condenser fan did not functioning
If the fan did not functioning well, the car engine temperature would increase, thus the air-cond would not cold enough. The solution is to exchange the fan motor so that the fan would functioning as normal again.
Second, there is a short circuit in the system
Most the spare parts such as compressor, fan, cooling coil and also fan blower needs electric for functioning. When there is short circuit, the problem would mostly occur on the relay or fuses. Besides，it would also because of the break of the wiring system.
Third, the cooling coil has already dirty and cover up with dirt
In this condition, the wind blowing out would become very less but the temperature is still fine. Our advise would be take out the cooling coil and clean it. After cleaning, we would refill back the gas. This is one of the problems that not just solved by topping up air-conditional gas.
If we can exclude all those factors, we can normally define the problem by not enough gas. The professional said there is about 100g to 200g of gas leaking from the rubber pipping each year. This can be say as natural leaking. From our experience, there is still normal if the car air-cond top up gas once in a year or two years. If the car air-cond not cold again after top up around 6 months ago, we can consider there is gas leaking.
