A/C compressor turns on and off?

[Tornexted]

I don't know whether the previous owner had the AC working but when I went to add a half can of refrigerant, the compressor would kick on and off every 2 seconds. In addition to that, when I removed the hose from the low pressure port, you can hear an audible hiss coming from the port leaking refrigerant, don't know if that's normal. Any help is appreciated, thanks. The AC knob is set to max and the AC button is pushed in. My 6.5 does rev down a bit when the compressor kicks in.

 

[Dariusz Salomon]

Hi-first question is-what is your ride? Second-do you know how long was the AC empty? If over a year then I'd start with replacing seals(o rings) and valves. Also add PAG (oil)with dye-it will save you some money as if the system is leaking you will lose the gas but at least it will show you where does it leak from.
The "every 2 seconds" compressor's action is due to the fact that there's little gas in the system if I'm not mistaken.

 

[Tornexted]

Hi-first question is-what is your ride? Second-do you know how long was the AC empty? If over a year then I'd start with replacing seals(o rings) and valves. Also add PAG (oil)with dye-it will save you some money as if the system is leaking you will lose the gas but at least it will show you where does it leak from.

Hey there, it is a 96 K3500 single cab with a 6.5 turbo diesel. I unfortunately don't know how long it has been empty for. I don't work with engines at all so replacing o rings and valves would be something of a great challenge, but if it isn't too difficult, I can definitely give it a try. Maybe a full video or a walk through of how to do this would be great. Thanks

 

[98 Nitro]

Usually if it kicks on and off like that it is overcharged.

 

[Tornexted]

I think it cycles on and off because there's no refrigerant in the system. That would probably make sense in this case, although an overcharged system would also show the same symptoms too. I highly doubt that its overcharged though because the truck was neglected for some time. I'm wondering though why after I charged the system and removed the hose from the low pressure port, why does the port hiss and leak refrigerant back out? Does the black cap that screws onto the port stop it from leaking?

 

[PlayingWithTBI]

Usually if it kicks on and off like that it is overcharged.

Not necessarily, it could be either. If it's low, the low pressure switch will open when it gets below 20 - 25PSI. When you get too much pressure the high pressure shutoff switch will open but that's closer to 330+ PSI but, it'll need to be hot with high ambient temps. OP - you need to put pressure gauges on it to see what's going on. If it's been sitting for over a year without a charge, you'll need to replace the receiver,/dryer and orifice tube (at a minimum). Then, evacuate the system for at least 30 minutes, shut off the vacuum pump and see if it holds a vacuum. Then you can start charging the system with the factory recommended R130A amount.

 

[PlayingWithTBI]

I'm wondering though why after I charged the system and removed the hose from the low pressure port, why does the port hiss and leak refrigerant back out?

Your Schrader valve is bad and needs to be replaced. The cap is only there to keep it clean. You can't rely on it to stop a leak.

 

[Aparke4]

Your Schrader valve is bad and needs to be replaced. The cap is only there to keep it clean. You can't rely on it to stop a leak.

This^

My A/C, 96 k2500 was blowing warmer and warmer and I topped it up using a fix a can from autzone but the system didn't take that much oil/ freon. Took it to a local firestone and the leak tested and sure enough- shcrader valve was culprit. They did an extraction and refill and its ice cold.

 

[Tornexted]

I'll be buying a vaccum kit with gauges soon to see what's going on. I was watching a couple videos last night on fixing this sort of stuff and it's not too complicated after all.. I'll be replacing the low pressure port and change out a couple o rings. And quick question, why replace the dryer? Does it go bad after years of no ac?

 

[Dariusz Salomon]

Since it's a single cab then your system is much more simple then dual ac-so good news here.First try to tightening the valves using pliers-you just grab and twist-then add some refrigerant and see if it hisses no more. I'd still replace them anyway.
As to dryer-read the insert. I just took a screenshot with explanation-I don't promote these guys.
Orifice tube for piece of mind and also to check if it contains any bigger chunks of metal and stuff-that will indicate any compressor damage.

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