a/c possible leak
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Drifting
Joined: Jan 2011
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From: Hamilton Virginia
a/c possible leak
Recently I went and try to recharge my a/c system on my 92 lt1. well it filled up fine and the a/c became nice and cool. Well the next morning I went to use it and it was warm again, so I figured I had a leak. Visually looking at everything I noticed on the high pressure line on the passenger side going into the firewall, there is a plug connector with wires going into a plug mounted to the metal a/c hose. it is damp and so is the hose directly under it and the other things. I am thinking this is the a/c refrigerant switch. Am I correct ?
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From: Lansing MI
If its mounted on the line itself then it must be. If it will empty itself overnight then you should be able to find the leak using soap and water. Like you were looking for a nail hole in a tire, watch for the bubbles .... At least then you will know for certain.
Thread Starter
Drifting
Joined: Jan 2011
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From: Hamilton Virginia
All the fittings were tight. I am pretty sure it leaked out at the pressure switch. It was not damp/shiny in that area last time I looked. I bought a can of a/c charge that includes dye. I do need to find a blacklight so I can be sure. I will get a new switch and change that first before I try it again, The refrigerant is too expensive to waste.
Thread Starter
Drifting
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From: Hamilton Virginia
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Team Owner
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From: Hartford WI
I did not run a vacuum test. The pressure was in the good. I am not sure what you mean did I seal after I changed the receiver dryer ?
All the fittings were tight. I am pretty sure it leaked out at the pressure switch. It was not damp/shiny in that area last time I looked. I bought a can of a/c charge that includes dye. I do need to find a blacklight so I can be sure. I will get a new switch and change that first before I try it again, The refrigerant is too expensive to waste.
All the fittings were tight. I am pretty sure it leaked out at the pressure switch. It was not damp/shiny in that area last time I looked. I bought a can of a/c charge that includes dye. I do need to find a blacklight so I can be sure. I will get a new switch and change that first before I try it again, The refrigerant is too expensive to waste.
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From: Lansing MI
Dye is less of a problem but its neither refrigerant or oil, unfortunately it displaces both. So one can with dye is ok but if you find yourself in a spot where you add a can per year (like many of us do) then it should be straight refrigerant. Don't even continue to add refrigerant with oil in it. You have to keep in mind that small leaks will only allow the refrigerant gas to escape, the oil and dye and everything else will remain, so it can really accumulate in the system over time.
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From: Lansing MI
I don't follow. Why exactly would you recharge it if the pressure was good? If it wasn't, you should have used a sniffer to check around for leaks before going to full pressure. Once you find the leak, evacuate the system, fix the leak and change the receiver dryer which you should do once you open up the system. After that, draw a vacuum and make sure it holds. Then pressurize the system with refrigerant and add dye
Team Owner
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From: Hartford WI
https://macsworldwide.wordpress.com/...ars-ac-system/
Receiver/driers serve three very important functions:
They act as a temporary storage containers for oil and refrigerant when neither are needed for system operation (such as during periods of low cooling demand). This is the “receiver” function of the receiver/drier.
Most receiver/driers contain a filter that can trap debris that may be inside the A/C system.
Receiver/driers contain a material called desiccant. The desiccant is used to absorb moisture (water) that may have gotten inside the A/C system during manufacture, assembly or service. Moisture can get into the A/C components from humidity in the air. This is the “drier” function of the receiver/drier.
Damage can occur if there’s excessive moisture inside an A/C system. It can cause corrosion, as well as possibly degrade the performance of the compressor’s lubricating oil.
The receiver/drier should be replaced any time the system is opened for service, and most compressor warranties require it. The desiccant is only capable of absorbing a certain amount of moisture, and when the inside of the system and/or the receiver/drier are exposed to the atmosphere, the desiccant can become very quickly saturated from humidity in the air. If this occurs, the desiccant is no longer effective, and will not provide future protection. Additionally, the filter inside the receiver/drier could be restricted by debris that may have been inside the system. This could diminish refrigerant and oil flow.
They act as a temporary storage containers for oil and refrigerant when neither are needed for system operation (such as during periods of low cooling demand). This is the “receiver” function of the receiver/drier.
Most receiver/driers contain a filter that can trap debris that may be inside the A/C system.
Receiver/driers contain a material called desiccant. The desiccant is used to absorb moisture (water) that may have gotten inside the A/C system during manufacture, assembly or service. Moisture can get into the A/C components from humidity in the air. This is the “drier” function of the receiver/drier.
Damage can occur if there’s excessive moisture inside an A/C system. It can cause corrosion, as well as possibly degrade the performance of the compressor’s lubricating oil.
The receiver/drier should be replaced any time the system is opened for service, and most compressor warranties require it. The desiccant is only capable of absorbing a certain amount of moisture, and when the inside of the system and/or the receiver/drier are exposed to the atmosphere, the desiccant can become very quickly saturated from humidity in the air. If this occurs, the desiccant is no longer effective, and will not provide future protection. Additionally, the filter inside the receiver/drier could be restricted by debris that may have been inside the system. This could diminish refrigerant and oil flow.
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From: Lansing MI
I can accept the inexpensive economics as a valid answer. I can accept a compressor failure and debris in the system also. As far as the desiccant and water contamination; well I see that as nonsense spewing forth from those selling ac parts and service.
H2O boils at 53 degrees Fahrenheit when contained in a vacuum of 29.5 in of mercury. This means if you draw a proper vacuum, then you will evacuate all the water vapor. Believe it or not, water boils at -24 degrees F at 29.91in of mercury, although your vacuum pump probably wont achieve that number.
H2O boils at 53 degrees Fahrenheit when contained in a vacuum of 29.5 in of mercury. This means if you draw a proper vacuum, then you will evacuate all the water vapor. Believe it or not, water boils at -24 degrees F at 29.91in of mercury, although your vacuum pump probably wont achieve that number.
Team Owner
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From: Hartford WI
I can accept the inexpensive economics as a valid answer. I can accept a compressor failure and debris in the system also. As far as the desiccant and water contamination; well I see that as nonsense spewing forth from those selling ac parts and service.
H2O boils at 53 degrees Fahrenheit when contained in a vacuum of 29.5 in of mercury. This means if you draw a proper vacuum, then you will evacuate all the water vapor. Believe it or not, water boils at -24 degrees F at 29.91in of mercury, although your vacuum pump probably wont achieve that number.
H2O boils at 53 degrees Fahrenheit when contained in a vacuum of 29.5 in of mercury. This means if you draw a proper vacuum, then you will evacuate all the water vapor. Believe it or not, water boils at -24 degrees F at 29.91in of mercury, although your vacuum pump probably wont achieve that number.
According to a guy HERE
The short answer is NO.
You don't have enough vacuum, even with the two stage pump. You would need the turbo pump to remove the moisture from the desiccant. The molecular sieve desiccant will release water when the partial pressure of water vapor above the desiccant is lower than the partial pressure of moisture inside the desiccant. To reactivate the desiccant you would need to reduce the pressure to less than 10 microns for as long as it takes for the water to migrate out of the sieve (hours / days?). The recommended procedure from UOP (who makes the sieve) to regenerate the desiccant is to heat to 600 degrees F and pass dry nitrogen through the drier for four hours. If you overheat the sieve, you will destroy the crystalline structure of the sieve and ruin it.
Buy a new drier and toss the old one in the garbage.
You don't have enough vacuum, even with the two stage pump. You would need the turbo pump to remove the moisture from the desiccant. The molecular sieve desiccant will release water when the partial pressure of water vapor above the desiccant is lower than the partial pressure of moisture inside the desiccant. To reactivate the desiccant you would need to reduce the pressure to less than 10 microns for as long as it takes for the water to migrate out of the sieve (hours / days?). The recommended procedure from UOP (who makes the sieve) to regenerate the desiccant is to heat to 600 degrees F and pass dry nitrogen through the drier for four hours. If you overheat the sieve, you will destroy the crystalline structure of the sieve and ruin it.
Buy a new drier and toss the old one in the garbage.
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From: Lansing MI
Again i could support the idea based on the economics, but its not necessary based on need.
I don't buy the idea of needing to reduce the h2o to 10 microns in an effort to restore the desiccant either. The guy you quoted even said "the molecular sieve desiccant will release water when the partial pressure of water vapor above the desiccant is lower than the partial pressure of moisture inside the desiccant". At the very best he has made some conflicting statements.
Whatever tho ... Go ahead are replace your drier, after all they are very inexpensive.
I don't buy the idea of needing to reduce the h2o to 10 microns in an effort to restore the desiccant either. The guy you quoted even said "the molecular sieve desiccant will release water when the partial pressure of water vapor above the desiccant is lower than the partial pressure of moisture inside the desiccant". At the very best he has made some conflicting statements.
Whatever tho ... Go ahead are replace your drier, after all they are very inexpensive.
Thread Starter
Drifting
Joined: Jan 2011
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From: Hamilton Virginia
Again i could support the idea based on the economics, but its not necessary based on need.
I don't buy the idea of needing to reduce the h2o to 10 microns in an effort to restore the desiccant either. The guy you quoted even said "the molecular sieve desiccant will release water when the partial pressure of water vapor above the desiccant is lower than the partial pressure of moisture inside the desiccant". At the very best he has made some conflicting statements.
Whatever tho ... Go ahead are replace your drier, after all they are very inexpensive.
I don't buy the idea of needing to reduce the h2o to 10 microns in an effort to restore the desiccant either. The guy you quoted even said "the molecular sieve desiccant will release water when the partial pressure of water vapor above the desiccant is lower than the partial pressure of moisture inside the desiccant". At the very best he has made some conflicting statements.
Whatever tho ... Go ahead are replace your drier, after all they are very inexpensive.
My a/c needed a recharge. I vacuumed it out and bought refrigerant. There was no pressure. I filled the system till the gauge was in the good. The a/c was nice and cool. I shut the car off put all my tools away and went inside for the evening. The next day in the afternoon, I went for a drive to the store and turned on the a/c. nothing but warm air came out. I popped the hood to see if I could see anything. I check all the connection and the ports, everything was tight and looked dull, till I noticed the pressure switch in the high pressure line going to the dash. It has an oilish shine on it and below it. it wasn't there before. I have a gut feeling that is where my leak is. the silicone like seal around the pressure switch came off when I wiped the switch off. I found a new one for $30 and I am going to replace it.
I have recharged a/c in about a dozen cars I have owned with great results and never replaced the dryer. Thank you for the advise but for now, I will not replace this one either.
Thread Starter
Drifting
Joined: Jan 2011
Posts: 1,853
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From: Hamilton Virginia
UPDATE.
The new sensor came in and I installed it, I recharged the system on Saturday morning. Everything nice and cool. Yesterday afternoon I went for a drive and the a/c was still blowing cold. So It looks as if I have fixed this leak. We will see how it goes.
The new sensor came in and I installed it, I recharged the system on Saturday morning. Everything nice and cool. Yesterday afternoon I went for a drive and the a/c was still blowing cold. So It looks as if I have fixed this leak. We will see how it goes.
Drifting
Joined: Oct 2015
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From: Shit Creek, USA
Is there a common spot for leaks on the C4? One or two specific spots that fail? I'm going to check that switch on my '95. It has the same symptoms (i.e. filled and gone in a day).
Aklim, it's not like you to waste ANY amount on an unscientific and absolutely necessary solution.
Where are the double blind tests, the control groups, the expert bloggers from the University of Phoenix?!? 
Somewhere the Guidions may be missing a bible.
I'll second (third?) that fattie.
