I just went to use my a/c for the first time since last summer and found out that it doesn't blow cold air now. I thought maybe the freon somehow leaked out, so I hooked up my recharger bottle that has a pressure gauge. First thing i noticed was that my compressor turns on for 1 sec and then back off again for 2 or 3 sec's and repeats that process. While it's turning on and off I look at my pressure gauge and it's on the low side of green while the compressor is off for 2 or 3 sec's and then when it turns on for the 1 second it starts to raise the pressure into the yellow part of the gauge and then it falls back down to beginning of the green for the 2 seconds as i it repeats the on/off process. Any ideas would be greatly appreciated.

 

Rapidly turning on and off means that pretty much all of the freon has leaked out. It often happens during times of dis-use.
I gather that you measured the hi-side pressure, but the colors tells me nothing, you got to give numbers.
It's the lo-side switch that turns on and off the compressor at around 24 psi.
Nevertheless, I guess it's time for a recharge (and a leak test).

 

Thanks for the quick reply wagon. I measure the one that is the larger diameter off of the canister. I assume and hope that is the correct one to put freon in. I did the same thing last year and go it to about 30-35 psi. Btw, I double checked the psi # and what it's doing is: when It turns on for 1 sec it tells me it's at about 27 psi and then when it turns off for 2 secs it goes up to about 50 and repeats. Is that a sign of low freon?

 

Strange that the pressure increases when it turns off, unless you're measuring at the low-side. Nevertheless I think you're running on fumes.
The canister is on the high pressure side and there you should get approx. twice the psi than the ambient in Fahrenheit is, system operating. You saying one valve is a large diameter leads me to believe it is an R12 system retrofitted to R134a and that the adapter on the low side valve is missing. Verify what is supposed to be in there. Filling takes place on the low pressure side. Here are a couple of A/C links that'll give you more information.:
http://aircondition.com
http://www.autoacforum.com

 

you should never just assume that you are dumping refrigerant in the right place at the right time or the right kind of refrigerant. you have to add it from the low pressure side so that the compressor can literally pull the refrigerant out of the can. also if you added R134a into a R12 system you just got yourself a big repair bill. R134a is a hydroflorocarbon and R12 is a chlorofluorocarbon you cannot purchase R12 at all because each molecule of chlorine can destroy up to 100,000 atmospheric ozone molecules aka O3 and you cannot purchase R134a in a container larger than 16oz or so (unless you are licensed) although R134a has no known detrimental effects to the environment . If you have contaminated the refrigerant you must recover all of it using a $4-800 recovery machine into a certified dot approved recovery cylinder using a $150 digital scale to weigh the refrigerant out of the system you may fill the cylinder to no more than 80% of it's rated capacity due to the expansion rate of refrigerant, this is done by putting the cylinder on the scale taring the scale taking the water closet stamped on the neck of the cylinder and multiplying it by .8 and filling it to no more than the resultant number. after all the refrigerant is removed you must pull the system into no less than 10"hg "vacuum" and wait while the pressure rises than do it again and again and again, at this point you would most likely know if you have a leak but that is not what i am trying to prove here. Never pressure test using a vacuum it pulls in contaminants from the atmosphere into the system. the reason that you would know that you have a leak is that the pressure would rise to 0psig multiple times possibly higher the first couple due to refrigerant evaporating from its liquid state within the system. at this point you can stop because it is redundant. then you should replace every component in your ac system because there is contaminated oil through out the system, just kidding. at this point you should pressure test using dry nitrogen because it is better than r12 for the environment, at no point should you ever introduce atmospheric air into the system oh I guess I didn't mention the gauge manifold that will run you between $70 - $250 which will allow you to do all this. while you have the system evacuated you should replace the filter dryer then you must hermetically seal the system and evacuate to 500 microns or deeper, add the correct poe oil and weigh in the correct charge of R134a. that is if you didn't ruin the seal on your compressor (common leaking point) no refrigerant no oil circulation, repeated short cycling bye bye clutch and compressor it is open driven and relies on oil.




all that I am saying here is if you don't understand 30% of what I'm saying and it is probably more.you have a lot more research to do BEFORE you just dumped refrigerant into your car.

 

Sorry I didn't get back sooner, I've been sick the past few days. I should mention that I had my clutch disintegrate on me in the past. So I had to put in a new compressor, which was already oiled and ready to put r-134 refrigerant in. It's been fine for 3 years. I went to check it again yesterday and at that time the clutch wasn't even coming on and the pressure was staying steady at 35psi. It didn't feel like it was blowing out cold air. I guess I only hope that i've been refilling it in the right spot. Like I said, it's the same way I put the refrigerant in the system in the first place and it's worked fine for 3 years. btw Wagon/Crazed, when I screw the fitting that is connected to the acumulator it blows air/freon out of it. The smaller port is connected to a refrigerant line running to the left of the canister. I'll look at those two sites you listed and see what they say about high side and low side ports.

 

if you connect it to the high side under normal operating conditions it will push oil and R134a into your can. definitely sounds like the guys caused a leak installing the compressor.