AC problem, possible blocked orifice tube?

[Aaron K.]

I have a 2003 5.7 RCSB that I've owned for about 6 months and the AC has always been flawless. The previous owner said he had replaced some AC components and had it vacuumed and recharged several months before he sold it to me. It's not my everyday vehicle, it's usually driven every 2-3 days because I need a truck or just because I feel like driving it. It recently sat for a week without being driven or even started. It was at this time the AC stopped blowing cold, on its previous trip the AC worked great.

After looking around the engine bay to see if I could see or hear anything obvious, I found one of the AC lines was freezing up...






I went to AutoZone to rent gauges yesterday. This picture is with the gauges hooked up and the AC OFF.



This picture is with the AC ON



Here is video of the AC being turned on and off with the gauge hooked up. It starts with the AC just being turned on and then turned off midway through. The clutch is engaged the whole time the AC is on.

https://www.youtube.com/watch?v=Xf7ZeKzovoc&feature=youtu.be

Thoughts? Seems like a blockage, but I don't know AC systems very well and realize it could be a number of things. I wonder why all of a sudden? Seems like I at the very least need an orifice tube and the system vacuumed and recharged and all. I stopped by a local shop and they said they could do that for about $85 but couldn't guarantee that would fix it. What else can I do to diagnose the problem and what else should be replaced if I'm gonna do the orifice tube? Does the compressor sound a little loud? Maybe its not getting the lubricating oil it needs because of the possible blockage?? Thanks all.

 

[chopperman1]

Under-charged and a leak.... If it were a restriction you would have higher head pressure.

 

[Aaron K.]

Under-charged and a leak.... If it were a restriction you would have higher head pressure.

Thanks for the reply!

Would I be safe adding a can of refrigerant for diagnostic purposes? To see if I get a reading on the low side with the AC on and if the AC blows colder air?

Why would the low side be so high with the AC off anyway? I was surprised to see that, I was expecting to see no reading at all with it off.

 

[SilverStreak88]

Thanks for the reply!

Would I be safe adding a can of refrigerant for diagnostic purposes? To see if I get a reading on the low side with the AC on and if the AC blows colder air?

Why would the low side be so high with the AC off anyway? I was surprised to see that, I was expecting to see no reading at all with it off.

You can add some, but you should also add the dye to find the leak unless you have a sniffer.

 

[Aaron K.]

Added a can that I already had. Brought the low side up to 30 and the high side to 150 or so. The compressor never stopped probably because the refrigerant is still low and is probably the reason the low/high levels didn't fluctuate at all like it normally would with the compressor kicking on and off as needed. Gonna do some research to find the refrigerant capacity and proper pressures then grab a couple cans of r134a at the store.

 

[Ajwalk2008]

There should be a sticker on the radiator support or hood


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[chopperman1]

If it's running without cycling you are close. You will also start to feel the low pressure side (right before it goes in to the accumulator) start to get cold. If it were me I would hit it with a die pack. Let it run until low again, find and repair the leak. Evacuate and weight charge it properly.

 

[Aaron K.]

I looked all over the engine compartment but couldn't find the sticker with the info. Found something online that said 26 Oz and AutoZone's system said the same so went with that. Ended up putting 2 12oz cans in....AC is cold again, low side goes to 40psi, high side to 210lbs. The compressor still never disengages, at idle or when holding the RPMS at 2k for a minute or so. High psi got up to probably 320 which seems high, but I like I said I don't know AC systems well.

I'm gonna drive the truck the next few days so I can keep tabs on any changes.

 

[coolemoff1]

I'm an ac tech I recommend checking condenser for debris
Probably very dirty
Also you've got a leak so add a bit of oil should quiet it down a lot
But weigh the charge in !overcharge is as bad or worse in lots cases than undercharge


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[SilverStreak88]

I'm an ac tech I recommend checking condenser for debris
Probably very dirty
Also you've got a leak so add a bit of oil should quiet it down a lot
But weigh the charge in !overcharge is as bad or worse in lots cases than undercharge


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Will you fix my A/C? I'm tired of fighting it.

 

[coolemoff1]

We're do u live


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[SilverStreak88]

We're do u live


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Lol, I was just kidding, but I'm out of Houston. I've just come to accept that it's gonna work half ass so I leave early in the morning and late in the evening when the sun is gone and it works good. When it has to work in the sun it wont function properly, pretty sure the compressor is going again...

 

[Aaron K.]

I'm an ac tech I recommend checking condenser for debris
Probably very dirty
Also you've got a leak so add a bit of oil should quiet it down a lot
But weigh the charge in !overcharge is as bad or worse in lots cases than undercharge


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Thanks for the info. I added some oil as well and it did seem to help quiet the compressor down. I'm gonna let it ride for now with what I have in it until I find where its leaking. Then hopefully fix the leak and have it charged professionally.

 

[Aaron K.]

Its been about 2 weeks. Checked pressures the other day and was at 35 low side and 160 high side. It was about 75 degrees out when I checked. AC is still blowing as cold as when I first recharged it. Only place I can find a possible leak is the low side schrader valve. Sprayed some soapy water in there and it slowly bubbled. It had a cap on it when it all leaked out, but who knows if it was tight. I put a different cap on with an o-ring to help seal it. Just gonna have to keep an eye on it. I was thinking about getting one of those tools that let's you swap out the schrader valve without discharging the system, but have heard mixed reviews on them.

 

[coolemoff1]

Psi look fairly close for 75degrees just keep eye on it take evaporator temp at vents next 75degree day and post


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