AC on a 1992 Grand Am

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  #1  
Old 08-03-05, 06:36 PM
swarngill
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AC on a 1992 Grand Am

Hello! After a nice, somewhat costly vacation, I came back to find that the AC in my 1992 pontiac grand am does not work anymore. It seems like the air is actually warmer when the AC is on rather than just putting it on vent. Anyway, I still get that little noise like air is being letting out of a tire when I turn it off, but I am certainly not getting any cold air. Is there anyway to fix this myself, or am I going to have to take it to a mechanic? All I really know of AC units is that they are never cheap to repair? Is there a good do it yourself solution?

Thank you!
Swarn Gill
Washington, PA
 
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  #2  
Old 08-03-05, 07:34 PM
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What it sounds like to me, is that you have an vaccum operated system (vaccum is applied to various vaccum pods, to make different doors open and close, to give you desired heat, A/C, vent, defrost ect..) and that 1 or more of the vaccum lines under the dash has broken/come loose..Most likely the 1 you'd need to look at first, is under the dash, on the passanger side..I believe GM used green vaccum lines to control the pod for heat/temp..
 
  #3  
Old 08-03-05, 07:46 PM
swarngill
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Thanks

I appreciate your help...I am not super knowledgeable about cars as you might be able to tell from my incredibly detailed posts, but I am dedicated to trying to save money. From your description it seems that the part might not be expensive, but getting under the dash from what I know of cars is quite labor intensive, which could run up a bill at a mechanic. If the line is broken, are these lines available at any car parts store? Do you also have a feel for how much the average mechanic would charge to do this type of repair. Perhaps it is not as labor intensive for someone skilled for such repairs. To me it just seems so strange that it was working fine before I left and after not using it all for a month now it doesn't work. I guess complete inactivity can be worse sometimes than using it!

Cheers,
Swarn Gill
 
  #4  
Old 08-03-05, 07:56 PM
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The fact that you can hear it "hissing" is actually a good thing..You should be able to lay on the floor of the car, and look up under the dash, (you'll see different colored plastic lines/hoses).. listen and feel for the broken line. Once you've found it, you can usually splice/reconnect the broken halves with a short, small diameter rubber hose..Any autoparts store will carry hose small enough to do the job..The main body of this vaccum harness is usually under the dash, more on the driver's side, to the left of the radio and A/C controls..It'll have black, green, yellow, blue and red plastic lines..You can trace most of them from that area, to the different vaccum pods they connect to..I'd give it a try yourself, before taking it to a shop..DIY..
 
  #5  
Old 08-04-05, 10:42 AM
swarngill
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colored tubes

Well I haven't had too much success, but that doesn't mean someone else might have! Anyway, I opened up the panel under the dash on the passenger side. I saw the plastic tubes you mentioned. Most of them are encased in a larger black plastic tube, where they were exposed I could see the green tube, but it didn't really seem loose anywhere. You said to listen and feel. What exactly should I be listening for? Should I have the car on with the AC on while I am listening or the car off with the AC on...should I be turning the AC on and off while listening. I had great faith things might start to make sense when I got in there, but unfortunately that wasn't the case. I also ran into a snag on the drivers side, where you said the main body of the vacuum harness is supposed to be. The panel at the bottom had one bolt that would not screw out. Either the threads are stripped there, or the screw is screwy because I turned and I turned and it never came out. Thus I could not get that panel off there to see anything to the left of the radio and AC control. Do you have any suggestions about what tool I might use to get the bolt out? Is there any chance the problem with the AC is that there is no freon in there or something? I am not even sure where the AC unit is under the hood. Thanks!

Cheers,
Swarn Gill
 
  #6  
Old 08-04-05, 04:15 PM
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That hissing may be refrgerant leaking from the evap and/or the TXV. If the system pressures are good, then look at blend door, but that is not controled by vacuum. If you also have an airflow problem, these cars were noted for filthy evap cores.
 
  #7  
Old 08-04-05, 04:45 PM
swarngill
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blend door?

The hissing only comes when I turn the AC off...it is the same sound you hear in most cars when you turn the car off and then turn the AC off...just a short hiss and then silence.

I am not sure what a blend door is or where it can be found.

Cheers,
Swarn Gill
 
  #8  
Old 08-05-05, 03:37 AM
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you may just be hearing the pressures equalizing in the a/c system you should probably see a shop to have the a/c checked out.
 
  #9  
Old 08-05-05, 07:06 AM
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Bejay is correct, your G/A uses a TXV which (when is is getting old) will hiss. If you are not getting any cold air, I will shoot from the hip and say low charge(just because of the hissing). Probable leak point is the shaft on your compressor, older H5/6 compressors used only single lip seals on the shafts and they are prone to leaking. Look at your shaft for any signs of oil leakage. Most likely that, no not replace the whole compressor, replace the shaft seal with a new double lipped seal (13.00 bux at dealer) you can do this without removing the compressor, vac. then recharge.
 
  #10  
Old 08-05-05, 08:54 AM
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Instead of draining the system to replace the seal because you most likely don't have a vacuum pump. Get a cheap recharge kit and a gauge to check pressure. You can find a gauge for around $10 or so at a parts store little plastic thing that gives you enough info on the reading to know if you are low or high, it doesn't read pressure in psi. Then if low you can recharge the system with a can that has a uv dye and stock leak in it. Put that small can in, then top off with normal freon. Next time the system gets low use a black light in the dark and you will see the dye glow where the leak is. Which will allow you to know for sure where it is. No guess work involved with that, just because that is a common place to leak freon doesn't mean every car does leak it from there, plus you could have more than one leak.

Then you can pay someone to pull a vacuum and charge it after you have fixed the leaks/replaced the seals.
 
  #11  
Old 08-06-05, 12:17 AM
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Appology!

Swarngill- I must appologize for wasting your time! I totally mis-read your original message, therefore wasted a WHOLE bunch of your time. If I'd read the part of "I turn it off" I wouldn't have sent you on the wild goose chase..
Again, I appologize! The others are right, it does sound like a charge issue
 
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