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Discussion Starter #1
So, the ac stopped getting cold. I checked the compressor and saw that it kicks in but turns off after a few seconds. Then, a couple minutes later, it does the same thing again. It cant seem to stay on. Any ideas? Thanks
 

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1995 T100 2WD & 1993 MR2
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The compressor will cycle based on system pressures. Time to get the a/c serviced.
 

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2006 Corolla LE
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Have you charged the system recently? That usually happens when you overcharge it, at least when I did on mine a few years back.
 

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Discussion Starter #4
Thanks for the replies. I'll get a set of ac manifold gauges. Whats the procedure for testing? Thanks
 

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2006 Corolla LE
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I just use the gauge that comes with the freon refill. The pressure it should be depends on the temperature in your area. It's as simple as finding the A/C port in your engine bay and hooking up the gauge to get your reading.
 

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You could probably use either of these videos as a guide for how to charge your system. First one is the quick charge method that I do, second one is the more thorough method with emptying the system and filling it. If you do the quick charge method, the attached picture is the location of where you connect the charging hose.
305519

 

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Skip the quick-charge kits. Buy a set of gauges first and get readings. Is it low? if so you may want to get a UV dye kit to check for leaks before adding more freon otherwise it will likely just leak out again.
 

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Like others mentioned, don't use those quick charge low side only kits. They don't tell you at all what the high side is doing and that is highly relevant to system operation. Not just that, but their gauges are notoriously inaccurate. This combined with the fact that you have absolutely no idea how much refrigerant is in the already, has a high likelihood of leading to overcharging. Buy a set of gauges, a vacuum pump, a small food scale, and some refrigerant, and you can do most air conditioning repairs yourself.

I bought the above tools years ago and they paid for themselves immediately. Since then I've used them to save myself hundreds on my own cars and made hundreds more servicing systems for friends and coworkers.
 
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Discussion Starter #11
Thanks for the replies. I got an ac manifold and vacuum pump and hooked them up. Now, the compressor wont turn on at all.

Here's the full story. The ac was working fine but i decided to top off the freon with a quick fill. The gauge was apparently off and i overfilled it. The compressor would turn on for a few seconds and then turn off. After seeing the posts, i hooked up the manifold. The low side was at about 110psi and the high side at about 100. I vacuumed them both out for an hour or two and now, the compressor wont turn on at all, so i cant even fill it back up. Is there something i'm missing that needs to be done?

Thanks
 

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That is normal behavior, rewatch the linked video, when you're about to charge it, turn on the AC so the compressor will kick in once it has enough pressure built in to draw in the rest of the freon.
 

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yeah so you overcharged it... then you drain the system, when you refill it the car needs to be running with the AC on and as you fill it (you MUST use a set of gauges and a can of freon, not a quick charge kit) and it gets to enough pressure, the compressor will start cycling. You didn't need to fully drain the system you could've just removed the excess and it would have been fine. If the AC isn't quite cold enough you could have a clogged filter, blocked airflow on the condenser, or you could try running the system without the filter to get a bit more airflow....
 

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Thanks for the replies. I got an ac manifold and vacuum pump and hooked them up. Now, the compressor wont turn on at all.

Here's the full story. The ac was working fine but i decided to top off the freon with a quick fill. The gauge was apparently off and i overfilled it. The compressor would turn on for a few seconds and then turn off. After seeing the posts, i hooked up the manifold. The low side was at about 110psi and the high side at about 100. I vacuumed them both out for an hour or two and now, the compressor wont turn on at all, so i cant even fill it back up. Is there something i'm missing that needs to be done?

Thanks
Best thing to do before doing anything else is check the outlet temperature at the vents. If mine is working fine I won't touch it. Today in 90+ degree temperatures with 90+ percent humidity, the AC in my Echo was cooling fine at max cold thermostat, recirculate and lowest fan speed. When moving down the road it cooled well enough to increase the temperature setting and still be comfortable.
I found my brother a 1990 hilux pickup with a 4 speed, carb, and AC for $1800, which cooled about the same as my Echo. They just had to mess with it and ended up spending $450 to get it working the way it was before it had been touched. Low pressure and high pressure switches keep the compressor from cycling to keep from damaging things.
Remember, it won't work as well when you are sitting still, a moving vehicle will always cool better with outside airflow over the condenser.
If you know the system has not been serviced in a long time, then the cheap refill kits with the gauge have worked for me, but I bought one car that had a hole in the compressor from impact damage (I think) and after throwing away one cheap can I used compressed air to diagnose that one, then sucked it down to hold a vacuum and recharged it, then sold the car.
Classic "if it ain't broke don't try to fix it." Takes no tools to just see if it cools decently. Once you open it up it can get frustrating and costly. My 98 Sienna cools great and I am not going to mess with anything until it stops cooling great.
 

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Discussion Starter #15
I tried again and the compressor doesnt turn on. After vacuuming for 45 min, i connected the freon to the low side. It went to 95psi and i started the car with the ac on. After 15 min, the compressor still is off. Any ideas? Thanks
 

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I tried again and the compressor doesnt turn on. After vacuuming for 45 min, i connected the freon to the low side. It went to 95psi and i started the car with the ac on. After 15 min, the compressor still is off. Any ideas? Thanks
you're supposed to charge the system with the car running and the AC on. And are you using gauges or are you still trying to fill it with one of those quick-charge low side only kits??? 95psi sounds way too high for the low side.... Why did you fill it that high?

here's a video going over the basics.
 

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Discussion Starter #17
I followed the video exactly. Vaccumed it and then connected the freon with the car off. Then, opened the low side on the manifold with the car off. The low side jumped to 95psi because thats what the can sent in. Then, i started the car and turned on the ac. But the compressor isnt turning on. It worked last week before i ovefilled it.
 

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I followed the video exactly. Vaccumed it and then connected the freon with the car off. Then, opened the low side on the manifold with the car off. The low side jumped to 95psi because thats what the can sent in. Then, i started the car and turned on the ac. But the compressor isnt turning on. It worked last week before i ovefilled it.
If you filled it with the car turned off then you didn't do it correctly. Also Idk what you mean by the can sent in 95psi worth of freon.

It's possible you've popped a fuse or damaged something by overcharging it that significantly.
 

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Discussion Starter #20
There's supposed to be vaccum when i start the car? At what point do i open the freon flow? Thanks
 
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