A/c Issues...really High Low Side Pressure

[swey00]

2002 silverado 1500

5.3, 310k miles

 

The a/c was working when I purchased the truck. One of the service ports was leaking last year, so I replaced it and the a/c hasn't worked right since. So today I am trying to fix it. Static pressure was the same when I started, around 120ish if I remember right. I ran the vacuum on it for an hour and it was holding a vacuum.

 

So I started adding a can r134a and after most of the can was in the pressure on the low side started going up at a much faster rate then the high side. After one can is added, the low side is almost maxed on the gauge and the high is around 150 or so...

 

I am not sure if the compressor is turning on or not...Honestly I cannot remember ever hearing it kick on. My power steering whines so it makes it difficult to hear lighter noises.

[Carder09]

Though im not a 100% when it comes to the ac systems, but sounds like something might be clogging the system up, I belove there is an orifice tube somewhere that's a filter you can check and clean/replace, not sure if that is what's causing it but its a try, also you said the compressor isn't engaging when refrig. Added, maybe someone will chime in but I think there is a sensor that prevents the compressor from activating when refrig. Is low, that may be broke also.

[ChevyTech77]

Are you using a refrigerant charge can that has oil added to it? While they are handy for recharging a system after major component replacement, if you add oil to a system that doesn't need any, things like this can happen. Otherwise, you need to replace the orfice tube. It's in the high side line, right near the service port, if memory serves me correctly. Take the line apart at the fitting next to the high side service port and pull the orfice tube out with needle nose pliers. They are about $1.50 at your local auto parts store. Try that if your not over charged with oil or refrigerant.

[swey00]

Are you using a refrigerant charge can that has oil added to it?

 

no I am not using one with oil, just the cheap can from walmart...i am headed to buy an orfice tube here in a bit, i am pretty sure the whole line was warm when i was putting in the 134.

[HawkScot]

sounds like the compressor has not come on yet. You should see the low side go up and down and the compressor cycles. On my 94 pickup), I have to jumper the switch on the dryer to get the compressor to run until there is enough 134 in it to meet the pressure thresholds.