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1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 06-02-2007, 06:48 PM   #1
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Default AC Problems

My wife'* Bonneville has been having progressively worse AC problems for a while now. It started with the compressor becoming increasingly noisy when activated and then finally ceasing to cool the air or engage altogether. When I tested the freon pressure, it came up as nonexistent, so I pumped it full of freon again, and voila the compressor started working again (I assume it had some sort of low pressure shutoff feature). But even then, the cooling was nothing to write home about. Maybe a third of what it used to be. Just recently, despite keeping the pressure up, the compressor stopped engaging again. The pressure in the line is around 40 psi which tells me that freon is not the issue, the compressor is. Does this sound reasonable? I haven't spent a lot of time working on automotive AC problems, so I want to verify my thoughts on this. THe system does seem to lose pressure slowly over time, but it isn't gushing out freon. I just gave it a charge with the UV dyed stuff so I can find the leak, but I'm not sure that will work if the compressor won't engage. Am I looking at needing a new compressor or is there a quick fix to this?
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Old 06-02-2007, 06:57 PM   #2
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40 psi ? Is that with the compressor not running?

If it is than you are still low on refrigerant... But the compressor should cycle on and the pressure should drop...

You have the V5 compressor which is a Variable unit... Once you turn it on it doesn't shut off unless its Blazing hot, or does not have enough pressure on the low side to keep the pressure switch closed...

If you are at 40 Psi with the compressor off you may still be low on 134a...

If you have 40 Psi while the compressor has been on a while than you my have it charged properly and could be having compressor issues..

If you have the proper system pressure and can't keep the compressor cycled on you may have a bad Compressor Clutch Relay...

There are a few possibilities, but its hard to say for sure without looking at it..

So the above is just a few things that you can look at..

Someone with a service manual for a 96 may be of some help to you as well..

Good Luck

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Old 06-03-2007, 12:29 AM   #3
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Just so you have proper info, a competent shop would put leak detecting dye in your system, and check for evidence of this dye leaking some time in the future. Freon has to go SOMEWHERE. If the leak is at your compressor, then the likely diagnosis would be to replace the compressor.

Your compressor is also a candidate for problems since it was making noises.

Is replacing your compressor an option?

That'* what mine required.
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Old 06-03-2007, 03:01 AM   #4
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Quote:
Originally Posted by jr's3800
40 psi ? Is that with the compressor not running?

If it is than you are still low on refrigerant... But the compressor should cycle on and the pressure should drop...
Yes. Before when the pressure was zero, the compressor kicked on when I hit 25psi. Now it hasn't kicked on as of 40 psi.

Quote:
You have the V5 compressor which is a Variable unit... Once you turn it on it doesn't shut off unless its Blazing hot, or does not have enough pressure on the low side to keep the pressure switch closed...

If you are at 40 Psi with the compressor off you may still be low on 134a...

If you have 40 Psi while the compressor has been on a while than you my have it charged properly and could be having compressor issues..

If you have the proper system pressure and can't keep the compressor cycled on you may have a bad Compressor Clutch Relay...

There are a few possibilities, but its hard to say for sure without looking at it..

So the above is just a few things that you can look at..

Someone with a service manual for a 96 may be of some help to you as well..

Good Luck
I will try a little more freon tomorrow, but more than 45 psi is listed as too much pressure, so I don't want to go much past that.
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Old 06-03-2007, 03:03 AM   #5
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Quote:
Originally Posted by Bugsi
Just so you have proper info, a competent shop would put leak detecting dye in your system, and check for evidence of this dye leaking some time in the future. Freon has to go SOMEWHERE. If the leak is at your compressor, then the likely diagnosis would be to replace the compressor.

Your compressor is also a candidate for problems since it was making noises.

Is replacing your compressor an option?

That'* what mine required.
The freon I added today has a UV dye in it and I have a blacklight ready and waiting to find where it'* leaking, but since the compressor won't cycle, it can't get to the rest of the system. I have no problem with replacing the compressor, but I want to make sure that is my problem before I do. They are a little spendy.
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Old 06-06-2007, 11:36 PM   #6
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So I was able to get the compressor to kick over once I added more pressure to the system. It just needed more than I originally thought. So I added the rest of the can of dyed freon to the system and looked for leaks. No dice. However, I could hear a hiss coming from the area of the compressor. That was Monday night. Now I'm back to thinking the compressor is the issue. I checked it again tonight and it had lost enough pressure that the compressor wouldn't kick on again. I put another can of dyed freon in and looked around with the blacklight and there is no sign of leakage anywhere, except for the hiss that I heard the other night. I pulled out an old stethoscope and listened to every part of the system and the only place the hiss became pronounced was when it was on the front of the compressor pulley. I'm guessing the leak is underneath that pulley, probably at the input shaft seal where I wouldn't be able to see the dye with a blacklight. So although the compressor works, it leaks and to my knowledge rebuilding it is more trouble than its worth.
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