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Discussion Starter #1
have a 1999 gmc sierra 5.3 4x4 (newer body style)

i just put a brand new a/c belt, condensor, and belt tensioner in hopes the a/c would work since its about 100* here... i took it to a local shop to get it re charged since lines had been off and all that... the said it held great pressure but they cant figure out why the a/c doesnt work. the compressor comes on and you can hear truck idle down but it only comes on for like 10sec and goes off for like 30 the whole time the a.c is on... so i thought they were full of it about not holding pressure so i got my own gauge out and checked it and it has like 170psi which is in my waring zone on my gauge.. the shop wants to replace my compressor and lines saying they are (stopped up) and its going to cost around 750 bucks.. im just not going to pay that... any input
 

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You need 1.3lbs in all trucks that do not have dual climate control.

Though, from what I'm understanding, your a/c system has been opened and stayed open...Might be a good idea and replace the expansion block/orifice tube. There's no telling how much trash is in the lines since it's been opened up.
 

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You need 1.3lbs in all trucks that do not have dual climate control.

Though, from what I'm understanding, your a/c system has been opened and stayed open...Might be a good idea and replace the expansion block/orifice tube. There's no telling how much trash is in the lines since it's been opened up.

excuse my ignorance on this i know nothing about ac systems. im trying to find out so a shop doesnt screw me.. what exactly is expansion block/orifice tube? and where is it located
 

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okay went and let some out its right where it needs to be according to my gauge... the compressor is running the whole time now and the ac line is freezing but yet no cold air in the cab?
 

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okay went and let some out its right where it needs to be according to my gauge... the compressor is running the whole time now and the ac line is freezing but yet no cold air in the cab?
Your cabin filters may be clogged up. Check under your air box under the dash on the passenger side, there should be a length wise lid with like a 5 or 5.5mm bolt holding one side. You probably have a cover over your hvac box. Take the cover off and you'll see your hvac box.

Take your filters out, one will be visible, the other will be stuffed inside, you need to fish it out. Replaced with new cabin filters, put it all back together, done.
 

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Discussion Starter #8
Your cabin filters may be clogged up. Check under your air box under the dash on the passenger side, there should be a length wise lid with like a 5 or 5.5mm bolt holding one side. You probably have a cover over your hvac box. Take the cover off and you'll see your hvac box.

Take your filters out, one will be visible, the other will be stuffed inside, you need to fish it out. Replaced with new cabin filters, put it all back together, done.
yeah i replaced my cabin filters last weekend when i changed air filter and my oil... those are good... but now i had a buddy watch the gauge and when i rev the motor up the gauge jumps from the warning zone down the the full zone over and over...
 

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Your HID Preferred Vendor
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yea its def over charged, would this by why it would be working correctly or do i have other problems
you need it evacuated and put where its supposed to be by somebody who has the equipment and knowledge to do it right. i passed my automatic transmission ase with flying colors but the a/c one kicked my ass (on the ac portion). i would find a new shop
 

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JUGS Racing
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You need 1.3lbs in all trucks that do not have dual climate control.

Though, from what I'm understanding, your a/c system has been opened and stayed open...Might be a good idea and replace the expansion block/orifice tube. There's no telling how much trash is in the lines since it's been opened up.
Youre confused. You replace driers/accumulators when you open the system. O tubes and expansion valves aren't affected when you open the system to replace parts.

To the OP definately take it to a shop that knows how to read A/C gauges.
 

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00Silverado
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You need to 100% replace the accumulator and its highly advised to replace the orfice tube as well.
 

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i had this issue with my jeep, it turned out that the temperature selector was not moving from hot to cold the knob would move but the internals would not move.
 

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JUGS Racing
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i had this issue with my jeep, it turned out that the temperature selector was not moving from hot to cold the knob would move but the internals would not move.
Blend door actuator was bad. Most likely whats going on with the OP if the low side line thats going into the evaporator is freezing.
 

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Discussion Starter #16
thanks guys alot of great info, im taking it 30 min to a different town where i know it will be done right, i will check the blend door act before i take it up there as soon as i look into where it is and figure out how to replace.. if that doesnt work i will deff be taking it to a shop.
 

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cunts
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+1 on replacing the accumulator/drier and orifice tube ANY time you open the system. Also, when you get a new orifice get the variable rate(?) orifice tube. It's about $20, but it is well worth it.
 

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Discussion Starter #18
okay seriously what the heck is up with shops around here.. i took it to a diff shop and dropped it off they called like 2 hours later and said it was done. i went to pick it up and asked what was wrong and they said it was a half pound low on freon and that it works great now (at this time im thinking bs i know its not fixed no way) so anyway i go out start it up and drive it around and of course it doesnt work. i raise hell and told them i wanted it fixed and checked out, not just add freon and call it done... the owner of the shop just said i had major problems with my truck and refunded my money. i went home and i changed the blend door act. its working like it should now and i can feel the knob rotate when i switch from cold to hot and hot to cold. but i still have no A/C...

are both line under the hood supose to be cold with the a/c on? the smaller line on my ststem is the only one geting cold and its only cold for the first part of it, when it ends and connects the the larger hose type line its hot..
 

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JUGS Racing
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Where the small line ends and the big line starts is where the orifice tube is. The temperature change is normal cause thats what the orifice tube does.

What did the owner of the shop mean by "major problems". They probably dont have anyone that can read a/c gauges. They only know how to recover and charge a system. Sucks that you cant find a decent shop in your area.
 
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