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A/C Pressure issues?? Flush time.

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Old 07-22-2014 | 06:51 PM
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Default A/C Pressure issues?? Flush time.

Here's one I'm sure has been covered before but wanted to post about anyway.

Got a '94 GTS in here that shelled a compressor clutch and needed some going through. So I pulled the compressor and gave it a good look over and saw nothing that I thought was odd or out of place so I installed the new one. Did the usual leak test, vacuum and began to fill. I noticed the high side was jumping way ahead of the low side as far as pressures as it was being filled up so stopped everything. You don't normally see 15L and 350H unless there is a blockage at the expansion valve. So pulled it all back down and started to tear in to it again and this is what I saw at the expansion valve under the cowl.



Greatness huh? If it's got these dessicant bits up here, the entire line from the drier to the front and rear expansion valve is full of it.

Started from here by pulling the lower line off the bottom of the car at the junction for the rear air and the firewall and spent a bit of time getting that 3 foot long line empty. Here's what came out of that one alone.



Pulled the drier off and between the wife and I, my flush kit, Wurth brake clean and flush stuff and the compressors it took us right at two hours to get just that line and junction cleaned out. Each blast of air or flush would cause a shot gun effect of pellets blowing out of the three open lines. What fun.



I feel for anyone who has to go through this messy job but it's important to be totally thorough or you will be back in to do it again. Might take a week to get all of this stuff cleaned up.
Old 07-22-2014 | 07:16 PM
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As Sean shares, AC work isn't really something I recommend as a DIY effort unless you really know what you are doing. It's way too easy to see that a system is underperforming, and ASSume that blindly adding a can or two of refrigerant will bring it it back to perfect health. Most folks are unprepared to even start a serious diagnostic process, and totally unprepared for a system clean-up of this magnitude.

What's the most probable cause of a drier/dessicant bag failure like this? Using the wrong oil in the system, the wrong drier for the oil used, or oil that's not compatible with the 'old' oil residue.

The '94 GTS is not a R-134a conversion issue generally, but I'm a little puzzled by the R12 fittings in the pictures. Is this a very early one that originall had R-12? Just curious since I was under the impression the switch was made somewhere in the '93 production period.
Old 07-22-2014 | 07:18 PM
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Bob, where do you see R-12 fittings? This is a factory R-134a car.
Old 07-22-2014 | 11:30 PM
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Sean, thanks, for sharing. I wonder if this is what was happening to that car in Houston that had gone through 4-5 compressors. Last I heard he finally go the AC working and didn't know what had caused the past failures.
Old 07-23-2014 | 12:52 AM
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Originally Posted by SeanR
Bob, where do you see R-12 fittings? This is a factory R-134a car.
Looks like R-12 fittings on your yellow hoses. Did I misread them?
Old 07-23-2014 | 01:14 AM
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Sean can "right" an A/C issue. He got mine blowing ice cubes when it's 100 deg outside.
Old 07-23-2014 | 01:20 AM
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BTDT, total PITA. Believe me, I feel your pain, seeing the caviar in the expansion valve raised my pressures a notch...
Old 07-23-2014 | 08:41 AM
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That yellow hose is part of an A/C flush rig. At least it sure looks like mine!
Old 07-23-2014 | 09:37 AM
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damn that sux Sean,
thanks for posting pictures of what you found ,
and why you had a reason to look.
I hope you can get all of the contaminates out of the system.
Old 07-23-2014 | 10:35 AM
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Originally Posted by dr bob
Looks like R-12 fittings on your yellow hoses. Did I misread them?
Yep, that's the flush bottle and hose.

This morning is pulling the seat and pulling the parts from the rear A/C apart, the coupler that goes up in to the body under the seat is clogged full, going to be another fun day.
Old 07-23-2014 | 11:33 AM
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Wow, Sean, and thanks for posting too.

Question for the AC experts; Both of my cars have leaks, is it OK to use a leak dye, if so what do you recommend please?

Thanks in advance,

Dave
Old 07-23-2014 | 11:40 AM
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I'm not a fan of putting anything in the A/C system except oil and refrigerant. Dye isn't going to hurt it though but will say that I've never used any. Yet. Almost all of the leaks I've encountered can be found visually with nitrogen and a bottle of soapy water. Those leaks that are too slow to find via that method can be found by cleaning every joint/hose/sealed area very well and over the course of time look for oily deposits. Now that I said that, I'm sure I'll end up having a car that I can't find by those methods and will have to resort to dye and UV light.
Old 07-23-2014 | 11:44 AM
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Dr. Bob, here's a better look at the flush container. Add some flush medium of your choice, pressurize it and go make a mess.

Old 07-23-2014 | 11:47 AM
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Thanks for the quick response Sean as that is exactly why I asked the question, I don't want to clog up the system and was thinking that using a dye may do just that.

Both cars blow very cold w/ a fresh charge of 134a, however only last but a week.

Thanks again,

Dave
Old 07-23-2014 | 12:00 PM
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Originally Posted by davek9
Thanks for the quick response Sean as that is exactly why I asked the question, I don't want to clog up the system and was thinking that using a dye may do just that.

Both cars blow very cold w/ a fresh charge of 134a, however only last but a week.

Thanks again,

Dave
Dye won't clog anything up so no worries there. If you've got a leak large enough for it to be gone in days then find someone that has a tank of nitrogen and let them pressurize it up, spray everything that looks like it could leak and watch for bubbles.

We've got a '93 here also, it was losing approximately 10psi over 10 minutes, that we took everything apart looking for a leak and a couple of hours of head scratching we found the leak on the suction hose (by the low pressure port) and the bubbles were slowly popping up there after a majority of the water had flowed away. You'd think that would be the first place we looked (it was) but didn't see it right away. Now waiting the 3 days out of Germany for the hose. Key is taking your time and going over everything a few times with the soapy water. Sometimes the leak is easy to find, sometimes not.


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