A/C CORDOBA98

Hi everyone. I have a problem with the A/C in my wife's '98 Cordoba. It's always worked perfectly, the best thing about the car, but for the last month it hasn't been cooling. Here's what I mean: the compressor works perfectly, there are no leaks, I've recharged it, drained it, and recharged it, even changed the type of refrigerant... but it's not cooling. The mechanic who recharged it gave up and said it could be a blocked valve because the pressure should have reached 15 bar, but it never went above 6 or 7 bar.
I'm hoping someone can help me out because things aren't great right now for a new car.
Thanks. Cheers.

That circuit is designed for R139 refrigerant; if you use another type, it won't work.

If you've tried another refrigerant: I understand it causes reactions in the rubber seals and gaskets, and something could get damaged.

Also, the oil is immiscible (meaning it can't be mixed with other oils). And besides, it's an oil that oxidizes when exposed to air (it loses something, or moisture gets in, or something like that; I don't remember exactly).

Solution: You need to inert the circuit.

1st - Pull a vacuum.
2nd - Inject helium (the helium will cause everything to slosh around).
3rd - Pull a vacuum again.
4th - Make sure there are no leaks.
5th - Inject 10 milliliters of oil for R139 systems (add dye if you think there might be a small leak).
6th - It's very important to check the compressor brand in your system, because the refrigerant charge (in grams) depends on the brand (for example: Bosch 750, Lucas 800, El Pato 350).

The issue with R139 is that the A/C has a bulb filled with R139; if you use a different refrigerant, the bulb won't open and the air conditioning won't work.

Now that I think about it, of course what's broken is the bulb;
it's an aluminum block with two tubes passing through it and a ball on one side. It's near the firewall on the right side of the car in the engine compartment; I think it has a plastic cover on that car.