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2006 chevy trailblazer_ls_ext
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Discussion Starter #1
I have been having an issue with the A/C on my V8 EXT for a while now. The basic problem is the passenger side is ice cold, however the drivers side is not, and the rear a/c is not. They are both only "cool" causing it to take a long time to cool off the interior. If I leave it on recirculate everything will eventually get cold, but it can take a long time especially if it is really hot out. I have tried various states of charge and it seems to have no effect. I have changed out the drivers blend door actuator as I thought perhaps it wasn't moving fully and some heat was blending in. I fiddled with it a bit this morning as things are heating up again here in FL. It was 80 degrees out and I had readings of about 40/150. I have tried adding a bit more freon before but it doesnt seem to help. One thing that I find strange is that under the hood, the lines dont get very cold like I am used to finding. Really not even sure how it cools at all! Suggestions please. Thanks, Roy
 

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2004 chevy trailblazer_lt
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You mention you had readings of 40/150 when it was 80 degrees out. Are you citing the low and high side pressures? If you are, I think your pressures are a little low. According to my handy cheat sheet (Diagrams: System Pressure Chart), it looks like your system is low on R134a. Even if you do not have a "leak", AC systems do loose refrigerant over time, so if nothing has been added after 14 years, then it's about time for some R134a to be added.

Please only add R-134a, and not R-134a with sealant. Also, remember the best way to do this is to have your system evacuated of refrigerant, then using a vacuum pump, pump it down for a at least a few hours, then refill the system by weight. These systems are finnicky when it comes to amount of refrigerant they like. Too little R-134a is better than too much R-134a. You can look up the proper amount of R-134a here: Compressor Oil Capacity Guide

Good luck!
 

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2006 chevy trailblazer_ls_ext
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Discussion Starter #3
I have tried adding freon to where the pressures were a bit higher but still in range and it doesnt seem to make any difference at all. I have not tried completely sucking it dry and refilling it, I guess it could have gotten diluted over the years, it takes about a pound a year to bring it back every spring. If that works it will certainly be the easiest and cheapest solution.
 

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I would say that if it looses around one pound a year, then you have a significant leak and it should be tracked down and fixed. Additionally, I would also be concerned with oil loss with a chronic leak.
 

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Discussion Starter #5
Yes I will have to find the leak and draw it down and recharge it. Up until it started giving me grief its just been easier to spend 5 bucks a year for a can of freon and 5 minutes recharging it.
 

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I hear you. I just don't want you to wind up with a seized up compressor due to a lack of oil. Not fun. Been there twice.

Good luck!
 

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Discussion Starter #7
So I have icy cold goodness in my A/C now, but things went a bit weird to get there. I couldn't find where the leak is in spite of trying for about an hour, so I went ahead and replaced both schrader valves, the orifice tube, and the few seals I could get my hands on without ripping too many things apart since I really wasn't sure what was wrong with it at this point. I vacuumed it down for 45 minutes put 3 ounces of oil in for good measure and started to fill it up. The specs said it should take 41 OZ but by the time I had two cans (24 OZ) I already had pressures of 60/325 and not much cooling. At this point I figured something was wrong. I wondered if my PCM electric fan kit was perhaps not moving enough air at idle and this is why my pressure is so high. This also would explain why I didn't have much cooling before as I was always watching the high side pressure as my guide for when I had enough freon in. So I grabbed a hose and sprayed down the evaporator. Well the pressures took an instant nosedive as expected and I was able to get the other can and 1/2 in. Here is the weird part. The pressure never went back up high again. I left it sit there blowing cold enough to freeze meat for 15 minutes and it stayed at roughly 55/225. So any education you can give me as to why this might have happened I appreciate. Thanks for the advice it got me headed down the right road to figuring it out.
 

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I think you mean you sprayed down the condenser which is in front of the radiator. The evaporator is in the dash. If by chance you did get a water hose up into the dash, then never mind sentence #1.

It sounds like there is/was some moisture (water) inside your AC system that decided to freeze up in the condenser (weird because of all the heat being released, but who knows as anything could be possible) and when you watered it down, it melted and the system went back to normal.

I know when I add refrigerant to one of my vehicles, I monitor 3 things, the low side pressure, the high side pressure and the temperature of the air coming out of the center air duct. I also go slowly so the refrigerant can equilibrate properly between the gas and liquid phases. I then monitor the air outlet temperature and try to get the lowest temperature possible. When I get close to the "perfect charge" so to speak, I'll barely open the valve to the refrigerant can for about 5 to 10 seconds, close it and then watch the thermometer I put in the air outlet for about 5 minutes. If it goes down, I'll repeat the adding of a little more refrigerant. If the temp goes up, then I know it's just slightly overfilled (which I can live with).

Next time you need to add R-134a, replace the accumulator just to make sure you have plenty of dry desiccant in the system to absorb any moisture that might have leaked in over time. Water likes to bind tightly to the desiccant and it needs heat in addition to a vacuum to thoroughly dry the desiccant, and it's quite hard to heat an accumulator adequately when it's installed in a vehicle.

Glad to hear it's working!
 

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Sounds like the condenser was dirty and when you hosed it down you cleaned it off or less likely the the engine cooling fan clutch decided to start working.

I would be tempted to pull the grill so you can spray water straight into the condenser to try and clean it off better, spraying it at an angle could possibly bend the fins.
 
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