The gas is the cheap part. The compressor that failed because the system ran low is not.
Every hot season somebody arrives here having had their air conditioning filled twice in a year and wanting it filled a third time. It is worth setting out plainly why we will not do it, because the reason is not the gas.
Start with what normal looks like. A sealed system loses a very small amount of gas over years through the seals, and after six or seven years a properly done service that recovers, evacuates and refills to the correct weight is sensible maintenance. That is not what we are talking about.
What we are talking about is a system that was cold in January and warm in April. That is a leak, and the size of the leak is measurable: we recover what is left and weigh it, and the difference between what should be in there and what is tells us roughly how big a hole we are looking for.
Now the expensive part, and this is the bit nobody is told at the cheap refill. An air conditioning system carries its compressor oil around in the gas. A system that is low on gas is a compressor being lubricated by whatever is left, running hot, in thirty five degree air, for months. So the two hundred rufiyaa of gas you lost is not the loss. The loss is a compressor at the end of the year, and a compressor and receiver and a flush and a fresh charge is a figure that makes people sit down.
So the order here never changes. Recover and weigh. Put the system under nitrogen and watch it for an hour, because nitrogen is dry, cheap and harmless and it either holds or it does not. If it holds, stop: there is no leak worth chasing and your warm air is something else. If it does not hold, dye and an ultraviolet lamp and every joint, the condenser, both hoses, the compressor seal and the service ports, until we can point at it.
The something else is worth its own paragraph because it is so common. The condenser sits at the very front of the car, ahead of the radiator, catching salt off the road and insects and dust, and on this island they block solid. A blocked condenser cannot shed heat, so the system runs at high pressure and blows warm however perfect the gas charge is. Add a condenser fan that has stopped turning and a cabin filter that has become a felt mat, and you have three cars in a week whose air conditioning is fixed without a gram of gas.
One last thing, and it is the reason this is on the website rather than said at the bay. Please do not buy the tins with sealant in them. They are sold everywhere and they are marketed at exactly the person in this article. What the sealant does is set where it meets moisture, which is the leak, and also everywhere else it happens to be when it meets moisture, which includes the expansion valve, the condenser and, if the car ever comes to a workshop, the inside of a recovery machine that costs more than the car. We have turned cars away for it, which we hate doing, and it is cheaper for everyone if the tin is never bought.