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Ac help

The ac on my 98 mazda 626 is not cooling. The compressor cycles on and off every 2 seconds or so. I put a gauge on the Low pressure port and it cycles with the compressor between around 25PSI and 55 PSI.

Does this mean anything to anyone?

Thank you in advance.

You can’t determine how the AC is performing by just monitoring the low side pressure. You need to also monitor the high side pressure. And for that you need a manifold gauge set.


You are low on refrigerant, you have a leak and need service.

That’s probably true, but you can’t be certain without measuring the high side pressure too. Maybe there’s an obstruction. If so, adding more refrigerant would just make things worse.

If the OP is at the point where they will either go without or only spend enough to buy a can of R-134, then they have little to lose and might as well try it.

If the OP must have working AC, then it would be better for them to go to a good AC shop and get it properly diagnosed and fixed.

The compressor cycling on every 2 seconds is a classic example of a system low on refrigerent.That’s all you need to know.

You need someone with experience in A/C repair to diagnose and repair the leak in the system.

Two seconds is a very short cycle. I’m guessing the AC system is low on refrigerant.

I’d take this to an AC shop. IMHO, automotive AC does not fall into the DIY category. You need specialized equipment and expertise to properly service the car’s AC.