AC Performance

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Tonyrodz

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Giod

Good point. The Schraeder valve on my high side port was leaking slowly. A full charge only lasted a few months. Since I
replaced them it’s lasted years. You do have to evacuate the system to change them though.
There was dye in the one valve and inside the cap when I pulled it off to add freon. Can I use reg/tire shrader valves?
 

PG01

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There was dye in the one valve and inside the cap when I pulled it off to add freon. Can I use reg/tire shrader valves?
I would put the tip of a knife and carefully pull it up tony, not too hard just easily pull it up.

Im not sure if auto parts store sells the a/c retrofit kits anymore but if you have one or can grab one I would use the innards of that. I dont think the tire valves are same size but i may be wring
 

Rocket Man

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There was dye in the one valve and inside the cap when I pulled it off to add freon. Can I use reg/tire shrader valves?
I don’t think so, I bought the right part. Wasn’t going to chance evacuating the system and refilling it with $100 worth of shit just to possibly watch it leak out.
 

UmmScott

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Hey guys... new to the forum and I am a refrigeration tech for my work.
Thought I'd give some insight/input to anyone having AC trouble.

First off, always make sure the blend doors are moving to the full cold position.
Next, your front AC will always always not be as cold at first as the rear.
The rear has an expansion valve, front has an orifice. The exp valve can adjust itself for changing load conditions, the orifice can not do that.

2nd... before even thinking of checking the charge, check airflow airflow airflow!! Yes it's the most important! Check your condenser coil, it needs to be clean.
Check that radiator fan. On a hot hot day with the ac on and building head pressure, that fan should be roaring and moving air, not sitting there on low speed and barely doing anything. Get the GM fan clutch, not aftermarket or retrofit to the electric fans. It will work much much better.
3rd.. our systems need to have the EXACT weigh in charge. If you go to Wally world and buy those stupid cans, not only have you put air into the system, but you have no idea how much is in there. I think it's a full 3 pounds for front and rear ac systems. Take it somewhere and have the charge pulled and weighed in. That way you know if it's either leaking and was low, or was overcharged.
Yes..you WILL put air into the system if you use one of those cheap crappy can with hose setups. Feel free to message me for more info on why.

4th.. here is a BIG BIG performance test to see if your compressor is pumping correctly.
Start vehicle, turn all ac systems on high and recirculation. Let the cab temp get down to 75ish or lower.
Next, completely turn off the rear ac and turn the front ac to full cold but lowest blower speed. Your discharge temps should go into the low 40s to high 30s from the center vent.
Also, your compressor should be pulling down to 30psi and eventually cycling off via the clutch cycling switch and come back on shortly.
If your compressor can NOT pull down to 30psi or below with the car nice and cold, then there is definitely a problem. Compressor could be weak, rear exp valve could be stuck open, system could be overcharged or have air in it, poor condenser airflow, etc.
This is a very very good test and if your vehicle cant do this, then there is definitely a problem.

Always here to help guys :) this is a great forum

Sent from my SM-G975U using Tapatalk
 

Rocket Man

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Hey guys... new to the forum and I am a refrigeration tech for my work.
Thought I'd give some insight/input to anyone having AC trouble.

First off, always make sure the blend doors are moving to the full cold position.
Next, your front AC will always always not be as cold at first as the rear.
The rear has an expansion valve, front has an orifice. The exp valve can adjust itself for changing load conditions, the orifice can not do that.

2nd... before even thinking of checking the charge, check airflow airflow airflow!! Yes it's the most important! Check your condenser coil, it needs to be clean.
Check that radiator fan. On a hot hot day with the ac on and building head pressure, that fan should be roaring and moving air, not sitting there on low speed and barely doing anything. Get the GM fan clutch, not aftermarket or retrofit to the electric fans. It will work much much better.
3rd.. our systems need to have the EXACT weigh in charge. If you go to Wally world and buy those stupid cans, not only have you put air into the system, but you have no idea how much is in there. I think it's a full 3 pounds for front and rear ac systems. Take it somewhere and have the charge pulled and weighed in. That way you know if it's either leaking and was low, or was overcharged.
Yes..you WILL put air into the system if you use one of those cheap crappy can with hose setups. Feel free to message me for more info on why.

4th.. here is a BIG BIG performance test to see if your compressor is pumping correctly.
Start vehicle, turn all ac systems on high and recirculation. Let the cab temp get down to 75ish or lower.
Next, completely turn off the rear ac and turn the front ac to full cold but lowest blower speed. Your discharge temps should go into the low 40s to high 30s from the center vent.
Also, your compressor should be pulling down to 30psi and eventually cycling off via the clutch cycling switch and come back on shortly.
If your compressor can NOT pull down to 30psi or below with the car nice and cold, then there is definitely a problem. Compressor could be weak, rear exp valve could be stuck open, system could be overcharged or have air in it, poor condenser airflow, etc.
This is a very very good test and if your vehicle cant do this, then there is definitely a problem.

Always here to help guys :) this is a great forum

Sent from my SM-G975U using Tapatalk
Awesome info, you need to put this in the Tech section please.
 
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Tonyrodz

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I jumped that plug20190901_182814.jpg
Clutch still didn't turn on. The ac light on the button is on steady, doesn't flash. Ac belt is still on too. I haven't had a chance to clean the condensor--although it's less then 2 yrs old.
20190901_170322.jpg
 

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