Compressor is working allowing hot air to blow but only when on high--mechanic says possible leak and wants to put dye to find leak--so my compressor is fine? or the air wouldn't be blowing t all?

first I would look under the hood with the a/c on to see if the compressor clutch is working, if not it could be a simple fix by adding refrigerant, if you have a leak then, you need to take it in and have a test performed on it, most shops have a dye that they put in to see where the leak is

several reasons why ac not blowing cold. Most common a freon leak causing system to be undercharged. electrical and component failure may also be a factor. You need a set of gauges. find the compressor start engine with a c off the compressor clutch wont be engaged now turn it in on and see if clutch engages. If it engages you need to know what your low and high side readings are. You should have your system diagnosed be a seasoned pro...... If clutch does not engage you probably are low on freon. Put dye in the system so you know where the leak is when it leaks again. you can buy freon with dye already in it.

I would recharge it then see if that fixes the problem. if it keeps blowing hot the you will more then likely you will need to replace the compressor. but I would check all the line first you might have a leak or one of the lines could have come loose

First things first.....You must have the air conditioning system hooked up to an a/c system machine and then checked for leaks and also read low and high side pressures. If there are leaks then low Freon (R134a) content and low refrigerant oil can cause the a/c system to not engage the a/c compressor which basically means you will not have proper defrost functionality nor regular air conditioning. Most shops, when working with your air conditioning, will install air conditioning dye to assist them in locating leaks and is the first step in diagnosing all a/c systems. Post the findings after thw

Normally due to low freon. Also, notice if the a/c compressor clutch engages, as it will not if the freon is low.

You have a leak somewhere, possibly at the compressor or a pinhole in the condenser. An a/c leak detection kit can be bought relatively inexpensively at your local parts store, allowing you to inject dye into the system in the same process you would charge the system; an ultraviolet light (included in the kit) is used to see where the dye is leaking and pinpoint the leak for a proper repair.

More likely the recharge blew a o-ring and you have a leak. When your Cavalier was blowing hot air and a recharge fixed it that means it was low on freon which lets o-rings dry out, go back to the shop and have them leak test it. They use a pressurized dye to find the problem. If it's blowing it's not the cooling fan relay, they may have meant compressor relay but I'd have a leak test done first it's not expensive and easier that chasing unknown possibilities.

Why do they want to replace the compressor?noisy?If you can put a charge on the ac then it's hot again after a day,then you have a leak.all the ac lines have o-rings where they are connected.without put dye in the system you wont know for sure.So I would try that first.

Blowing air just means the fan is working.
No cold air is usually just low refrigerant
but it could be a bad compressor as well.
Have the refrigerant level checked first.

there may be a leak in the system.An a/c shop can put dye in the system to find the leak.It may be a bad o-ring