Found with a meter, not with a guess

We can, and we will not, and that is the whole reason this workshop has a reputation.

A system that went from cold to warm in a few months has a leak. Gas put into it leaves again, and while it is low the compressor is running without enough oil, so the cheap refill in March is part of why the compressor fails in November. Book the leak test instead. If it turns out the system holds pressure perfectly, the fault is elsewhere and you have lost nothing.

First by weighing what gas is left, which tells us how big the leak is. Then by filling the system with nitrogen and watching whether it holds for an hour.

If it does not hold, dye goes in with the oil and an ultraviolet lamp finds it, joint by joint, at the condenser, both hoses and the compressor seal. If it does hold, there is no leak worth chasing and we go looking at the condenser, the fans and the cabin filter, which is where the answer sits more often than people expect.

No, and one of the commonest faults costs nothing to fix.

The condenser sits at the very front of the car catching salt, dust and insects, and when it is blocked solid the system simply cannot shed heat however much gas is in it. Washing it out from the front is part of a service here. Add a fan that is not spinning and a cabin filter like a felt mat and you have three warm air conditioning systems that need no gas at all.

Not because of better equipment. Because of how we charge.

A workshop paid for parts has to find a part. A workshop paid for hours can spend the hour that finds an earth strap, and about one time in six that is exactly what the answer is. We are also happy for the answer to be cheap, which is a strange thing to have to say out loud.

Start with a place in the Saturday clinic. Half an hour there will tell you whether this is an hour of work, two days of work, or somebody else's job.

Bring the car with the fault happening if you possibly can, even if that means driving around for twenty minutes to get it hot.

And write down what you notice: when it happens, in what weather, hot or cold, moving or standing, and what else was switched on at the time. That note regularly saves the first hour of measuring, and you are the one paying for hours.

It is one of four things and they feel identical from the driver's seat: a battery that collapses under load, an alternator that is not charging, a bad connection or earth eating the voltage on the way, or something awake that should be asleep.

The first three are found in the diagnostic hour. The fourth, a parasitic drain, is found by leaving the car with us for a couple of nights and pulling fuses one at a time, and there is no instrument that shortens it. We tell you at the end of the hour which one you have.