I would check your freon r-22 they have bottle at your local auto part store with gauges; It will tell you if your freon is low if it is you can then fill it, If it shows there is freon then it may be the compressor but the freon an easy check and only 35 for a large bottle. Remember to not overfill it if you do need it. If you here hissing while you are installing stop see if you can locate the leak, Here is a DIY youtube for adding only use
Freon (a brand name of refrigerant) is the blood of your air conditioner.
Without enough refrigerant, your AC can’t cool your home properly, leaving you sweaty and uncomfortable.
Not only that, but a low level of refrigerant can severely damage your air conditioner, just like a low blood count damages your body. We’ll explain why in more detail.
Here are the signs your AC is low on refrigerant...and what you need to do to get things back to normal.
1) House takes forever to cool off
If your AC is taking longer than normal to cool the home, you may be low on refrigerant.
Because refrigerant is what absorbs the heat in your air. So without enough of it, your AC can’t absorb enough heat to cool the air well.
In other words, think of refrigerant like a heat sponge: the smaller the sponge, the less it can absorb.
2) Supply vent is blowing lukewarm/warm air
If you’re really low on Freon, you’ll notice that your supply vents are blowing lukewarm/warm air.
Now it makes sense why your home is taking forever to cool off!
3) Higher than normal electric bills
Due to lack of refrigerant, your AC runs much longer than needed to cool the home, increasing your energy bills as a result.
4) Ice buildup on refrigerant line
Go to your outside AC unit (the one with the spinning fan). If you see ice building up on the copper refrigerant line, then you may be low on refrigerant.
When low on refrigerant, the inside AC unit’s evaporator coil (the part that cold refrigerant flows through) gets too cold, causing cold liquid refrigerant to flow back the refrigerant line.
This causes the surrounding moisture on the refrigerant line to freeze up.
Oh, but there’s more.
Eventually the liquid refrigerant will make its way to the outside unit’s compressor (the “heart” of your AC).
This flowback of refrigerant will damage the outside unit’s compressor. You see, liquids can’t be compressed, so when the refrigerant flows into the compressor, it’s quickly converted into thousands of pounds of hydraulic pressure, and something (valves, rods, plates) will break.
Compressors are extremely expensive to replace and, if yours doesn't have a valid warranty, you’ll probably end up replacing the entire outside AC unit since it’d be more cost efficient.
5) You hear a hissing/bubbling noise
The only reason you’d be low on refrigerant is due to a refrigerant leak (refrigerant isn’t used up like gas in a car, so escape through a leak is the only conclusion).
And if you have a bad refrigerant leak, the refrigerant makes a hissing or bubbling noise as it escapes.
Next steps: How to fix this problem
If they find a leak, they should repair it (if possible) before adding more refrigerant. Adding refrigerant without fixing the leak will cause the refrigerant to escape again, and you’ll have this problem all over again. And older R-22 refrigerant is super expensive now.