Freon leaking. what is most common problem for

Dyes are pretty foolproof - you are probably not looking with a UV source where it is leaking. Common leaks that are very hard to find are at the evaporator core and connections to it (in the HVAC box).

Check to see if the AC clutch is engaged and turning the AC unit. If it isn't, check the freon pressures. Low freon will trip a pressure switch and prevent the clutch from engaging. This is a more common issue, some freon leaks our over time at the shaft seal.

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.

It can leak out over time through what are called Shrader Valves. They are replacable but they can and do leak. They are located where you put the freon in at the high side and low side ports. It can also leak out from the A/C compressor if the seals have failed. There are mane areas it can leak out from but the Shrader Valves are the most common places. AS LONG AS YOU DONT TURN THE A/C ON, YOU CAN'T CAUSE ANY DAMAGE. IF YOU TRY TO RUN THE A/C WITH A LOW CHARGE YOU WILL BURN UP THE A/C COMPRESSOR AND CONTAMINATE YOUR A/C SYSTEM AND WILL HAVE TO REPLACE A LOT MORE STUFF WHEN YOU DO GET IT FIXED. THE FREON IT WHAT MOVES THE LUBRICATING OIL THROUGH THE SYSTEM. SO JUST LEAVE THE A/C OFF UNTILL YOU IDENTIFY THE LEAK AND REPAIR IT.

There's a handful of reasons freon will leak and with time all cars usually do. Condensor, receiver/drier, compressor are just some of the more common ones.

All vehicles will leak a miniscule amount of freon from the seals throughout the coolant lines, you can use a leak detector additive when adding freon or use a freon gas leak detector to find any substantial leaks in the system by guiding the probe around all the components while the vehicle and ac are running. You could use a heldheld freon charger with a built in pressure guage provided you have the correct fittings, otherwise I'd recommend having both your low/high pressure sides monitored while adding freon and making sure your compressor is turning on and off properly as the high pressure side reaches its peak.

Freon is first issue. Possible freon leak. Air condensor leaking. Bad Compressor. Bad fuse. Many possibilities.

look for the thick pipes vs. the thin pipes and a quick connector that goes on to the hose that fills the r134a via a can of freon.

Or, do you mean, where is the freon leaking out of? The freon leaks out of o-rings, seals, and possibly the compressor.

I had a compressor changed in my 1990 Cadillac Deville because it was leaking there. This is a common problem on older cars.

Good luck.

the evaperTOR CORE IN DASH HAS A HOLE IN IT.REAL COMMON

Sounds like you lost your refrigerant in the system, couple options here, 1. Take the chance its a very slow leak and just recharge it or have it recharged, sometimes vehicles will last all summer or even more, but keep in mind, if large leak you just wasted some money charging the system. 2. If it was mine, most repair shops can send a dye through the system and pinpoint where losing freon. Losing freon is the most common A/C failure and keep in mind can get costly if not fixed right.
3. Last but not least is the compressor, not as common of a problem as losing freon but still could be the problem, this is where taking it in somewhere that deals with air conditioning on a regular basis could troubleshoot this easily, but hopefully the compressor is not at fault as they usually run $200 or more.