Having issues with my stock AC unit in my 86 GT. It has apparently spring a SLOWWWWWW Leak according to my mechanic. Still blowing slightly cool after 4 months. Due to work cut backs (2 - 3 days a week) don't have the funds to put in a new compressor etc. Anybody have any experiences with some of the AC Stop Leak products on the market. As I indicated replacing the whole system right now is not an option but I don't want to keep filling up the Freon if none of these products work.

Thanks, Xlowes

NOT!!!

You need to find the leak and fix it. AC is one area where the concept of "Do it right or do it over" really applies. Stop-leak won't fix the problem, and it may permanently damage the system ... at which point fixing things can become VERY expensive.

Well speaking from Long Island where it's covered in snow, I hardly sympathize with you...lol, j/k but how do you know the compressor is at fault? You can get a Florescent dye and put it in the system and use a black light to find the leak. Any shop can do that or you can get the dye and black light yourself. Four months is a slow leak, it could be an o-ring, fitting or one of the switches. Pay attention to the compressor, sometimes the case gets porous over time and you will see a green tint on the housing under the black lamp.

Or I can send you some snow....

NO NO NO --- do not use stop leak! put in the dye -test and find the leak -do the repair --- you will be gald you did.

quote Originally posted by Marvin McInnis: NOT!!! You need to find the leak and fix it. AC is one area where the concept of "Do it right or do it over" really applies. Stop-leak won't fix the problem, and it may permanently damage the system ... at which point fixing things can become VERY expensive.

What he said

NO

Do it right with a new Accumulator, O rings, drain and refill compressor with 4oz of Ester 100 oil, the other 4 oz right into the accumulator. Coat new GREEN o rings in Ester 500, install components and seal it up. Hook up a vacuum pump and pulll 29.9 inHg vacuum for an hour to boil out all moisture. Then put in one of the three cans of R134a. The system will pull in a full 12oz can under its own vacuum. You dont even have to start the engine. Then, start it up and turn the A/C on max, full blower. roll down windows. the system will need only about 85% of the R12 charge, so 40 oz is now about 34oz. put in the second can HALF of the third, can, UPSIDE DOWN, shaking the can. DONT GET FROSTBITE cans will get VERY cold. 2 full cans and half of the 3rd can will total 30oz. Now you will need to adjust the pressure switch for R134a. R134a runs at higher pressures than R12, so you will need to adjust the switch so it turns off at 30PSI. This is where R134a causes the A/C evaporator to reach freezing. You DO NOT want it to freeze, so set it at about 30PSI off. Use a small screwdriver to turn the screw in the cutout switch, located in the front on the accumulator, clockwise to lower the pressure. Try this out for a while. Remember to use AS LITTLE refrigerant as possible to achieve proper cooling. If excessive cycling is noted (test with A/C on max and high blower) on an 80 degree day, then add more refrigerant, ONE OUNCE AT A TIME until excessive cycling has subsided. If there is still excessive cycling, then either there is low airflow (blower set on low, bad blower motor, resistor) it is too cold outside, or your eveporator is clogged with debris (this happened to me...mousenest) Do NOT go over three full cans (36oz), or too much liquid refriogerant will make it back to the compressor, severely shortening its life or causing failure.

Hope this little tutorial helps

Matt

Be very careful telling someone to turn a refrigerant can upside down when filling through the low side port...

If there is any liquid that does not turn into vapor before getting into the compressor, it will destroy your compressor.

Charlie

quote Originally posted by cptsnoopy: Be very careful telling someone to turn a refrigerant can upside down when filling through the low side port... If there is any liquid that does not turn into vapor before getting into the compressor, it will destroy your compressor. Charlie

You are always supposed to put regrigerant in as a liquid through the LOW side port. If you try to put it in through the high side, the safety pressure release on the bottom of the can will let go, and will probably freeze your hand. IF the correct amount is put in, eg. 34 oz, then the accumulator will hold it all, and none will get to the compressor. If you overfill it, like lots of people do (More refrigerant=colder temp, right? NOT) Then yes, liquid refrigerant can make it back to the compressor and lock it up.

Matt

[This message has been edited by mattman134 (edited 02-01-2011).]

Oh well, I learn something new everyday. Can you help me with a reference please? That really sounds wrong to me. Thanks.

Charlie

I don't know what's "correct" but I have discovered that its hard to get all of the refrigerant out without turning the can upside down. I haven't blown up a compressor, yet (5 A/C systems and counting)

quote Originally posted by cptsnoopy: Oh well, I learn something new everyday. Can you help me with a reference please? That really sounds wrong to me. Thanks. Charlie

I have personally rebuilt so many A/C systems in cars I have lost count. I have not had a single compressor failure. That is what the accumulator is for, to hold the liquid refrigerant. It holds it there, so it can finish boiling off before it gets to the compressor. If the system was overcharged anyway when you add refrigerant, then you CAN blow up the compressor. You can add refrigerant either way, I am just telling you the way I do it. When rebuilding as many A/C systems as I have, you learn to listen to the system and it will make certain sounds when the system starts to lock (liquid-slugging). You must also monitor the low-side pressure. Yoiu can charge liquid as long as the low-side stays below 50PSI. It also makes a big difference on the ambient temperature, as colder temps will cause slugging a lot sooner, as the liquid refrigerant cannot eveporate as quickly. I am not saying you are wrong, but I have never incurred a failure. Sure, I can give plenty of sources, but I am just saying How I recharge auto A/C. No need to prove either way, as people do it different ways.

Matt

quote Originally posted by Marvin McInnis: NOT!!! You need to find the leak and fix it. AC is one area where the concept of "Do it right or do it over" really applies. Stop-leak won't fix the problem, and it may permanently damage the system ... at which point fixing things can become VERY expensive.

The only fix that is available is a new compressor which is what the shop told me. That's why I was inquiring about the Stop Leak. As I indicated in my original post my job has been reduced to 2 - 3 days per week and I was hoping that one of the products I looked at would work as I don't have a Grand to put in to a new system.

Thanks, Xlowes

quote Originally posted by xlowes: The only fix that is available is a new compressor which is what the shop told me.

Did they say how they determined that? Did they say where and why the compressor is leaking? Otherwise, your shop may just be blowing smoke. The compressor is just one of many places a slow refrigerant leak can develop, and there's no reason to replace a compressor that just has a leaking seal.

My advice? Find another shop ... one that's both competent and ethical ... or learn to do it yourself.

[This message has been edited by Marvin McInnis (edited 02-03-2011).]