Think I killed my ac

[Flynbrd]

So the ac was blowing cool instead of cold. I've done ac stuff before so I have a general idea what I'm doing. Anyway I put about 20 oz in (system holds 28 right?) I slowly filled it, the psi slowly climbed from 38 psi to about 44 psi. I was shooting for 45 . I think I heard the emergency blow off for maybe a second. Now the car has pretty much no ac. The car is cycling the compressor on for only a few seconds . The psi on the low is now sitting way high 70 - 80 psi (account of the compressor not staying on I think) I tried to bleed off a few ounces off which did help the numbers a bit. My guess, I hurt the compressor or the system is still overcharged and that's why it won't run the ac compressor for more than a few seconds? Tomorrow I'll hook up the high side if I can find it and see what it's reading. Any theories for the compressor cycling on and off. Also how hard is it to replace? Oh outside temp was in the high 90s

 

[joegr]

This, this is why some of us keep saying to never, ever add or remove refrigerant without monitoring both the low side and the high side pressures!

If the low side is really 70-80 PSI with the compressor engaging and the compressor is cycling, then (1) the system is overcharged still, and (2) the evap temp sensor is bad (and was your original problem). This is all speculation from 10,000 ft. Real diagnostics is required. It is also possible that you blew your compressor and/or expansion valve.

The high side port is the easy one to get to. It's at the top left of the radiator, at the receiver/dryer.

 

[Flynbrd]

My hero

 

[Andrizzle]

I recently overfilled, but not by too much (I don't remember hearing anything blow off). Compressor would cycle on for like ten seconds, then off, then repeat.

My low side was only reading about 30-40PSI, though. So yes, you must monitor the highside when filling, or at least add very little and keep checking the operating conditions until it is optimally cold.

 

[joegr]

Yeah, I suppose that if his high side is really high now, it would cycle off just due to the high side over pressure. Of course, when all that excess refrigerant is vented out, he's going to lose some oil too...

 

[Flynbrd]

So I vented the high side for a few seconds before starting the car. (ugh you were right, took me about 3 seconds to find the port) Guess I vented about the right amount, the system started working with compressor staying on. High side was about 225 and the low was 37ish. I added just a little bit more to the sytem. Bumped the high side to 235ish and called it quits. The low side never got over 40 so I guess its flowing good? I ordered the a/c compressor switch from advance auto for 70$. Normally its 120 (local its 110), found a promo code that knocked 40% off.