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Some experienced advise needed...

Fishbone on Fri September 07, 2007 11:28 PM User is offline

Year: 1999
Make: Mercury
Model: Sable
Engine Size: 3.0 DOHC
Refrigerant Type: R134
Ambient Temp: 80
Pressure Low: 70-90
Pressure High: 125
Country of Origin: United States

Greetings: Last summer I noticed that our Sable's a/c was not running as cold as it had in the past. I managed to put in about a can and 1/2 of R134a into the system. I do not remember if it was the stuff that had compressor oil mixed in or not. It seemed to be OK for a while. The car sat for almost a year since we purchased a new vehicle for my wife last Sept. We decided to save the Sable for one of our kids who would be driving this summer. About a month ago our son became a licensed driver. He complained about the a/c so I dumped in about 1/2 a can of R134a. It ran OK for about a week and then warm air again. The compressor clutch would cycle on and off every few seconds. It would remain engaged when I jumped the switch. It should be noted that when I previously charged the system, I did it without the benefit of a gauge manifold. Just one of those cheapo hose gauges.
I purchased a gauge manifold set and a venturi vac pump. When I hooked up the gauge set I was getting a static pressure of about 70 PSI on the suction side and around 125 on the high pressure side. When I started the car, the gauge(s) did not move much. The clutch would not engage without the jumper.
Being concerned about the high pressure on the suction side, I decided to evacuate the system and start from scratch (now knowing actually how much R134a was in the system). I ran the pump for about an hour @90 PSI. About a tablespoon or 2 of water sprayed out of the vac. pump throughout the evac cycle. The system held a steady vacuum around 29 hg for a half hour before I started charging the system.
With the engine off I opened both high and low valves. About 1/2 a can flowed and that was it. I shut down the high side valve and started the car (still using the clutch switch jumper) in an effort to get the system to take more refrigerant. Very little went in. The can, manifold, and hose remained warm. The low side pressure went up to 90 PSI at times and the high side had trouble getting past 125. I managed to get about 3/4 of a can total into the system and then I gave up.
My guess is that something is clogging up the lines somewhere. Possibly the O-tube? Anyway, I purchased a new O-tube and a new accumulator (since you have to move it to get at the high pressure line I might as well change it out). I evac'ed the system out again ( about a tablespoon of water came out) and started moving things around but I have not yet cracked into the system. Again after the 2nd evac, the system held a good vacuum for almost an hour when I pulled off the manifold set.
I imagine once I get to examine the O-tube, I might get some clues what is going on inside. Am I on the right track here? Thanks, this is my first post. Very informative site.

Chick on Sat September 08, 2007 5:20 AM User is offlineView users profile

Several problems here at first glance. One, static pressure should always be the same on both high and low side. Are you sure your manifold set is "zeroed" in. Should be a set screw in each gauge face. Second, the venturi pump just doesn't cut it, but if it's all you have, so be it..(it actually sounds like you live near a "harbor frieght" tool store?? ??) Water should never be seen as a tea spoon full coming out of a pump, so most likely the air in your compressor is loaded with water.. Another reason I don't like venturi pumps... The stuff you've been adding (you said you had the little guage that came with refrigerant in the past) may be biting you on the backside now if it contained sealers.. But pull the O tube and see what it looks like. The pic below shows it's location hidden in the rubber insulation.. Also check out affordable DIY'er starter kits with an electric pump. Then you can follow the Vac/charge procedure listed here with the exception that you'll be filling by "weight" and NOt pressures. The pressures are to diagnosis the system once the proper amount of refrigerant is back in the system..Hope this helps..Feel free to ask any other questions as you go along..




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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Fishbone on Sat September 08, 2007 9:02 AM User is offline

Thanks for the quick reply. As far as the water goes, it has been a bit humid here lately and I do not have a seperator on my compressor. You are probably correct in your assessment that the moisture originates from the compressor. I'm not sure exactly how the venturi pumps work but should I assume that the water is simply bleeding off and seperate from the vacuum process?
Also, great photo of the bare liquid lines. It appears that there is a coupling where the o-tube is inserted. Should I break it while mounted it on the car or would it be easier to pull it entirely? Thanks again

Chick on Sat September 08, 2007 9:14 AM User is offlineView users profile

Just remove it where it is..It's far enough back where you can get to it...Hope this helps.

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Fishbone on Sat September 08, 2007 2:56 PM User is offline

I just pulled the accumulator and made my way down to the o-tube fitting. Opened it up without incident and pulled the tube. The oil residue looked OK BUT there were metal shavings embedded in the screen but it was otherwise clean. A few were the size of a pinhead. Is this normal wear for the compressor or did it croak? Thanks again.

Chick on Sat September 08, 2007 5:39 PM User is offlineView users profile

some specks are perfectly normal, as long as no burned oil, or other signs of compressor failure, but from what you desribe it sounds normal...Good luck..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

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