A couple of weeks ago I asked for some help with an air conditioning problem on my 93 sr5. About 25 lookers but no real help. Then I got advice from a friend and here is the answer. Problem, compressor does not engage. Did not see any power to it and could not get it to engage with direct input of power. Suggestions as to how to determine the problem did not pan out. Turns out there is a switch that blocks the power to the compressor if the system has low pressure. Probably to prevent running it dry and burning it out. Anyway, friend said to get a charging kit and about 8 cans of 135a and run the motor and keep feeding it cans. He said after about 4 of them the compressor would start to cycle. Just keep shoving stuff into the system until it is full. Did it and that did the job. We are cool now. Took 7 cans. If I had gone to a shop it would have been a couple of bills, actual cost was about $75. No signs of leaks (used the stuff with the lubricant - dye not needed - lube will leave oily marks wherever it leaks). So - all is well, money is still in pocket and I learned something. All the years of fooling with cars, never had AC so never paid much attention to it.

Wow 7 cans is a lot. The manual says the system takes 23 oz. I have some cans in the basement and they are 12oz..

I think there's a sight glass on the T100. When you stop seeing bubbles in it, you've got enough.

Last year walmart had a $30 kit with some cans & a crummy-but-did-the-job charging valve/hose.

where do you charge the system at???

on the low pressure side a/c valve tap. which is on the thicker aluminum line on the top left side under the hood.

Don't lose the cap. Only one that threads on right seems to come from the dealer. Ask me how I know <img src="/forums/images/graemlins/frown.gif" alt="" />

Yeah, I saw the sight glass but is is like one of those Delco battery sights. Just a little dot. Anyway, CSS with it to tell you the truth. If you do a little figuring, a totally empty system will take a lot of stuff, Gotta figure the compressor, lines, canisters, a/c heat exchangers, etc. It is a liquid, so if you use 6 cans it is only 72 ounces - 2.25 quarts - not much. After 13 years of life, the stuff will leak out somewhere over time, everything else does. A true leak through a fitting or the like will be very obvious even without the special dye some use - the oil in the 134a leaves a distinctive oil stain. Anyway, that worked for me. Sure cheaper than a shop doing.

Mine has a "L" on the low side cap and a "H" on the high side. Different sizes of fittings as well, so the recharge kits will only fit one of them - the right one.

Seven cans? I'm surprised you didn't hydrolocked the compressor. Normally on a complete replacement 3 cans is about average.

Regardless, I'm glad for you that your a/c is working well.

OK, a little more training please. Hydrolock the compressor? Does that means the thing wont turn?

Yes, a hydrolocked compressor will not turn.

When the a/c system has the right amount of refrigerant in it, the compressor has a gas coming into it, and mostly coming out of it. It's getting squished into a liquid form as it goes into the condenser, roughly.

If you get too much refrigerant in the system you start getting conversion from gas to liquid earlier. All the way back into the compressor itself.

And if you get way too much refrigerant in the system, you get liquid traveling throughout the whole system. Which can have you sucking liquid into the compressor. And compressors don't do well trying to squish liquids. They lock up. It's a transient locking. As the liquid squirts around the piston(s) the compressor will slowly continue to rotate. Many times it will also blow the seals out of the compressor.

This hydrolocking is the danger/bane of turning the recharge can upside down when adding refrigerant. True, it's a quicker charge. But you're sucking a liquid down into the compressor. Usually you get away with it. Sometimes you don't.