Hey guys, my a/c has suddenly crashed on me. I'm been trying to narrow it down and so far this is what I got. Both fans turn on. The compressor kicks on when I turn the ac on. It has about 75psi in the low pressure line when the a/c is not running, but zero when I turn it to cold full blast. Air comes out of the vents but, it's just mild (when it's set to cold) and the hot works fine. So I'm thinking it's some sort of valve on the low pressure line or perhaps something electrical, but I really don't know enough about it. Anyone have any ideas of how I can go about fixing this? Thanks.

 

Do you know that the compressor is cycling on and off? If you have a guage set, hook up the guage set while the A/C is running. Should be 200PSI on the high side and 0 on the low side. It sounds like you already have that. The electronics of the A/C pretty much turn the compressor on or off. There is a low side switch, when the refrigerant is low the low side switch goes in the open position and does not ground the compressor clutch and it does not engage. I think that you do not have enough refrigerant. Check if your Reciever/Drier or accumulator has a sight glass. If it has a sight glass you can add refrigerant without evacuating the A/C system. If you have a vacuum pump, you can do this. Also, if you have a vacuum pump you can put the A/C under a vacuum (with the gauge set) and see if it holds the vacuum. If it holds vacuum then you don't have any leaks.

 

I don't believe I have a sight glass, nor a vacuum pump unfortunately. Just clarification, but I can't just add r134 with one of those kits at autozone can I?

 

Well you could but the only problem is that you will have no way to know when you have added the correct amount. But you have to find/fix the leak before you refill it with refrigerant. Since A/C is a closed system, the refrigerant should never have to be recharged unless there is a leak. When did the problem start and did you have any accidents?

 

Yep, the problem started yesterday, but the accident was a minor one involving my passenger side bumper. The accident was probably 3 or 4 months ago, so I'm going to assume the leak is pretty small if that is the case. Do you think the leak sealer in some of the refrigerants will suffice?

 

I've never heard of leak sealer for refrigerant before so i have no idea on that. However, i would rather fix it properly than use stuff like stop leak. I've seen stop leak go bad, as in the heater core got clogged to hell. I would go about finding the leak. You can take it to a shop that has some fancy tools. At our school we have this high tech thing that beeps when it senses refrigerant. If you wanna go low-tech, you can buy some refrigerant that is R-134a and a dye. You put that through your A/C system and get a black light. You gotta be careful not to spray the dye everywhere otherwise you will not be able to spot the leak. After the dye is into the system, let it run a bit and get a black light and shine it around all the pipes, hoses, condensor, compressor and whatever else is there. The dye that i used last was green when you put the black light over it. That would be my preferred method b/c its pretty cheap and easy. Just don't be sloppy and you should be fine. My buddy was doing that and got the dye everywhere and caused himself more work.

 

Thanks for all the help. I didn't even stop to think that I may have a leak due to that accident, since it was such a long time ago.

 

You might not have a leak, but if the accident site was near any of the A/C compenents it is possible.

 

First of all year and model , it will help with diagnose

you need to hook up a gauge and let us know both the low side and high side pressures.

DO NOT under any circumstances add stop leak in the a/c system,, or anything else other than whatever freon it calls for r-12 or r-134a or dye , or reccomended a/c oil.

depending on the year of your car, the rec drier sits on the rt side behing the bumper ,, so it is possible a line could have a small leak also condensor and lines are in frt as well

if you are low on freon, you need to add freon and also put some dye into the a/c system , so you can properly identify where the leak is at especially if it is a small leak..you need an ultra violet lite to properly see the dye .. it is yellow green in color depends which you buy..

but first thing first let us know both pressures low and high ...

if you do not have the proper tools i would advice to let a shop handle this ..but if you plan on doing it yourself we will help you as much as possible , till hopefully you get it fixed

 

it is a 2001 ex, forgot to list that. I think you might be right on it with the leak at the rec drier. I followed the piping to check for anything obvious and saw that some piping was in the vacinity of where I got hit, though I'm still a little iffy of whether it's a leak or not. (The accident caused only a large scrape on my front passenger side bumper.) As far as the pressures, all I have is what is listed. The 0 psi in the low pressure line when it's full blast and 75 when it's off. The reason I can't measure the high pressure is due to my lack of supplies. No adapter to what I have, and I'm getting my readings from only a simple low pressure gauge. I think I may take your advice and visit a shop; it seems I don't really have the tools required.