A/C Diagnostic *HELP*
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A/C Diagnostic *HELP* When I first bought my car, it had icey cold A/C. After a few months of driving around, the A/C slowly started to get warmer and warmer, eventually to the point where there wasn't any A/C at all. I've decided to get to the bottom of the problem this weekend, but I need some advice as I am A/C retarded.
I'm picking up a can of the UV reactive freon stuff from AutoZone. I have the hoses to connect it all, and the best I can figure is to just plug the can into the silver canister in the engine bay with the appropriate fitting on it. Then I'll kill the lights, turn on a blacklight, and see where the leak is.
Does this sound like the right way to go about doing it? I'd really appreciate it if someone could educate me no the proper way to go about checking for this leak, fixing it, and then refilling the system.
Thanks in advance.
I'm picking up a can of the UV reactive freon stuff from AutoZone. I have the hoses to connect it all, and the best I can figure is to just plug the can into the silver canister in the engine bay with the appropriate fitting on it. Then I'll kill the lights, turn on a blacklight, and see where the leak is.
Does this sound like the right way to go about doing it? I'd really appreciate it if someone could educate me no the proper way to go about checking for this leak, fixing it, and then refilling the system.
Thanks in advance.
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From: Jacksonville, FL
You're on the right track - it'll come with instructions. Referigerant has oil it and will collect around where the leak is too. The fix will depend on where/what the leak is, and if you have to open the system to the atmosphere you'll need a vacuum pump to get the moisture out of the system before recharging.
If the system is already flat and the compressor doesn't come on as the pressure switch in the safety circuit, then its already got moisture in the system and pulling a vac on it is going to be required.
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Originally Posted by Alt
If the system is already flat and the compressor doesn't come on as the pressure switch in the safety circuit, then its already got moisture in the system and pulling a vac on it is going to be required.
Can I still check for leaks without it being vacuumed out first?
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Guess you could try putting a can in, don't know if it'll be enough pressure to find a small leak though if the compressor won't kick on. Since you have hoses/gauges have you tried a STATIC pressure test? Might be some left but not enough to tell the low pressure sensor to let the compressor come on. My helms says to park the car inside or shade, key off, read the ambient air temp then compare the pressures on the high and low side to the following for safe operation:
Above 60* - 50 psi
Above 75* - 70 psi
Above 90* - 100 psi
I'm assuming these are minimums. Sorry not much help, I do home AC but a novice when it comes to cars.
Above 60* - 50 psi
Above 75* - 70 psi
Above 90* - 100 psi
I'm assuming these are minimums. Sorry not much help, I do home AC but a novice when it comes to cars.
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I went ahead and tested with the U/V dye for leaks. I found a little bit of dye on the compressor, but a lot of things were reacting to the black light and it was pretty hard to tell if something was really leaking from the compressor.
On the other hand, I found a definite problem on a line leading to the condensor (I believe its the condensor, you'll see in the pic).
I ended up JB welding that piece of piping to try and stop the leak. The JB weld hasn't cured yet, but I'll test it tomorrow for leaks. If it doesn't hold, it looks like replacing that pipe would be a cinch, assuming I could find another one. I'm sure the dealer has one.
Hopefully the compressor isn't the problem, as I was quoted by two different shops. If its just this pipe, I'll be a lot happier. However, given the dye splatter that looked like it was on the compressor, it could be a problem as well.
On the other hand, I found a definite problem on a line leading to the condensor (I believe its the condensor, you'll see in the pic).
I ended up JB welding that piece of piping to try and stop the leak. The JB weld hasn't cured yet, but I'll test it tomorrow for leaks. If it doesn't hold, it looks like replacing that pipe would be a cinch, assuming I could find another one. I'm sure the dealer has one.
Hopefully the compressor isn't the problem, as I was quoted by two different shops. If its just this pipe, I'll be a lot happier. However, given the dye splatter that looked like it was on the compressor, it could be a problem as well.
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Yeah that's the condenser - looks like you found it! The pipe on mine looks a little different, but agree it looks like an easy replacement. If you replace the pipe yourself put new o rings in too. At 96* this summer it'll have 245-293 psi on it according to the AC performance chart. Good job.
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The o-ring wasn't really the problem, nor was it some sort of loose connection. I should have taken a picture, but right where the arrow is pointing in the second picture you can bend that hole circular piece down. Its cracked pretty bad. I'm hoping some JB weld will fix it, but if not, $45 for a pipe isn't too bad considering I'll have icey cold air again.
Given that the compressor isn't leaking...
Given that the compressor isn't leaking...
Originally Posted by Hugh betcha
Do yourself a favor and replace the damaged line.
Just remember, once you repair the leak you have found, put the dye in the system again and look for more leaks. Most of the time, there is more than one leak.
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Originally Posted by koolaid_kid
Just replace the line. JB weld will not (and is not designed to) hold pressure. You are taking the correct course, the dye is by far the best way to find the issue(s). One thing to mention: Once you have a leak-proof system, you will probably have to replace the dryer (but not before). The function of the dryer is to remove the moisture from the system. When it is open (leaking and/or part replacement) moisture gets into the system and the dryer loses its effectiveness (the compound which absorbs the moisture gets full and cannot absorb any more moisture). Many suggest pulling a vaccuum on the system to remove all air after the system is open (which happens when you replace a hose/line). This is good advice, but can also be simulated by having a can of refrigerant connected and slightly open, pushing any ambient air out of the system (for the most part). Both will work, but the vaccuum is the best method. I have always used the can method, always with success.
Just remember, once you repair the leak you have found, put the dye in the system again and look for more leaks. Most of the time, there is more than one leak.
Just remember, once you repair the leak you have found, put the dye in the system again and look for more leaks. Most of the time, there is more than one leak.
. The JB Weld actually held pretty well, but it was still fizzing out a little bit of dye. I swapped the new pipe on and had the system vacuumed out. Tested for leaks again, no problem. Filled it up with some freon with oil, and now my A/C is icey cold again. 
