Auto a/c problem?

Question

Ok I'm trying to recharge my Chevy G20 Van's a/c and have never done it b4 and I'm having problems....The compressor wasn't kicking on because the freon was so low...I checked it (with engine off) and it read about 20 psi...I started the engine and added some freon and the compressor started coming on but was cycling on and off....the pressure guage would read 55 psi and the compressor would kick on n drop it down to 25 psi and shut off and keeps doing it repeatedly every 2-3 seconds....I drove it some to see what it would do and it kept doing this and blowing warm air....I checked pressure again (with engine off) and it read 80 psi......am I over charged?...still undercharged or what...Idk if I am supossed to check it with engine on or off but with it on it goes between 25 psi n 55 psi with compressor cycling grr please help.

Answer 1

The compressor is cycling because it is low on refrigerant. When the compressor is kicking on, it is drawing the low pressure side down. The low pressure sensor is then kicking in, and turning off the compressor clutch. This cycle repeats itself, as you can see with the compressor coming on and off.

Add refrigerant until the compressor stays running, then get your pressure readings!

Answer 2

you're still low on refrigerant. It's cycling because the low side pressure is triggering the low pressure switch. Low side pressure should be around 35-40 and high side pressure around 180 or so but it also depends on what kind of refrigerant you have in the van, R-12 or R134a. R134a uses higher pressures. the ac system performance test is ran at 1500 rpm for 10 minutes with the system set on max ac. Usually at idle a properly functioning system won't cycle but at higher rpms it will. If you're not that experienced with sc systems you might want to take it to a professional who is properly equipped and certified to do ac system testing and repairs. the ac system pressures will also vary due to ambient temperatures and relative humidity. As ambient temp and humidity go up so does the pressures and the ac's outlet temp. The pressures need to be checked while the engine is running. When the engine is off, the system pressure will equalize throughout the system. That's what the hissing noise is when you shut the engine off after running the ac.

Answer 3

Driveway repairs to a/c by inexperience people with little equipment are rarely succesfull. You are assuming your only problem is the refrigerant charge, but the a/c system is a complicated one. Are you even using the correct refrigerant? G20s, except for the last models, would have had Rr-12, which you cannot buy. Unless you have one of the last models produces in the mid 1990s, or there is a sticker marking a conversion to R134, you are looking a $90 a lb for refrigerant that can only be installed by a licenced technician. If R-134 is the correct one for your van, you still need a technicial to look at it. If it leaks, refilling it is a total waste of time until the leak is found and fixed.

Answer 4

My Keeprite home AC didn't work properly. The service guy came and replaced a 35+5/440V capacitor and charged me $86 Canadian Dollars. Then he added freon gas in from 22PSI to 70PSI and charged me $192. He said the price for freon gas is $4/PSI. In addition, he charged me labor $155 for about 1.5 hours work in my home.

I felt ripped off. A simple search finds that a similar capacitor is about $14. Any one can tell me the price of freon gas in similar situation ? As a non-technical guy in need of AC service, how do I know if his charge is reasonable or not ? Can I complain to his company and get some money back ?

Please help.

Answer 5

I am guessing that your van has the R12 freon in it.

That will all need to be drained from the system completly, then refilled with R-134A.

Depending on the engine size, and the year of the van how much freon you need for the system.

Answer 6

check for a leak or just go to the mechanic