A/C is hurting idle and blowing hot air

[86VickyLX]

Okay well good news, my friend took a look at it. My compressor is still in good condition, the reason my idle is being effected is because there is no charge in the system at all; he said the system is attempting to do its job and suck charge but it cannot thus hurting idle. He showed me the bubble test on my visible A/C system and found a few minor cracks. He came to the conclusion it was the line near my pressure switch, and the high/low lines near the condenser that caused the freon to leak out. What I need is new o-rings for the high/low valves, new pressure switch, accumulator, recharge kit and after that it should be good to go. Will post back!

If there's no charge on the AC system, that compressor IS NOT SUPPOSED TO COME ON.

[sly]

the compressor will short cycle with no charge. It will come on for one second and shut off for 3-5 seconds.

[Stealthlead]

the compressor will short cycle with no charge. It will come on for one second and shut off for 3-5 seconds.

^^ It would/will do exactly as stated above, you can hear it trying to do exactly that. OBVIOUSLY I leave the system off as I did when I suspected an issue.

Also I'm getting the r134a kit so we can convert it over ;D

[86VickyLX]

the compressor will short cycle with no charge. It will come on for one second and shut off for 3-5 seconds.

No it won't. With no charge, the compressor will never kick on. Unless there's a problem with the pressure switch on the drier. If there's any kind of charge on the system, yes it will cycle, but not if it's completely empty.

[sly]

ok... completely empty.. yeah... but the slightest bit of charge (even if it's mostly air), it will kick on for a second. Any system that is just really low on refrigerant will try to work even though it won't get anywhere. And for most people (not the trained/professional mechanic types) blowing hot air means it's empty and once more refrigerant is put in and it's blowing cold air, it's full. it's semantics. I stopped taking my car to one older fellow who was a pretty good mechanic because he would continuously argue semantics with me instead of taking the "lay person terms" I was using and then telling me how it really was. I would do just what you're doing and say "NO! It doesn't work that way. Never has and never will."

Obviously, if the system is short cycling and someone claims it's empty and won't cool, it's probably just really low. If you've dealt with a few different people, who don't know the complete technical stuff about the system, and their cars' AC systems, you should know this. Save yourself, and everyone else, the frustration and explain stuff instead of just saying the person is wrong or the system has gone to shit.

[86VickyLX]

I did explain myself.

[sly]

but he also mentioned it had cracks in the system on the low side. This will allow the compressor to try to compress ambient air and will allow a non-vacuum condition. This means that the pressure switch will notice a slight change in pressure, but won't get enough of a change to keep things running. This causes a short cycle. Did you miss that part? If the system is completely sealed and completely empty (under vacuum), then yes, it shouldn't do squat because the pressure switch is doing its job of shutting the system off when there's nothing to compress. I've not met a single automotive AC system that will not try to compress ambient air (also, all systems in question are originally R-12 systems - 93 and older. About 6 or 7 so far... my experience may be limited, but it's still not deviated from any other one I've worked with. Never worked on an original R134a system except to top it up). Even a completely open system (hence having to disconnect the electrics to the clutch to prevent burning up the compressor with the defrost in a Taurus - no fun having something seize up).

that said... maybe all the systems had sticky pressure switches or worn switches that would stay engaged except when under vacuum and that's not supposed to be that way, but rather at low pressure. Unfortunately, from watching the gauges, they all seem to trip off around 5-10 psi which is less than 1 atmosphere (14.6959 psi), which would mean that if the system is completely open to the air, the pressure switch would never shut off at lower elevations. If my observations are correct, you'd have to be around 10K feet above sea level to start seeing the system never trip on.

If my numbers are off on what the sensors are supposed to work at and the ones I've observed are worn out, let me know. I have at least one sensor to replace.

[86VickyLX]

Well every box panther ac system including Brown Muscle's with a hole in the condenser did not kick turn the compressor. think about this. the pressure switch will not supply power to the clutch without at least 24psi. with a crack in a line. or an open system the compressor WILL NEVER TURN ON because atmospheric pressure is hardly ever over 1 bar. or 14.7psi at sea level. and. i'll prove it to you. before i swap out my compressor at scottfest.

[sly]

so the switches I've dealt with were bad since they would supply down to even 5psi in some cases. Here in lies the issue.

I'll look at replacing mine since it drops the gauges down to about 10 before cutting off.

Being a "shade-tree" mechanic and not having access to some of these specs (especially with air conditioning systems since it's ultra regulated and such) is rather cumbersome.

[86VickyLX]

so the switches I've dealt with were bad since they would supply down to even 5psi in some cases. Here in lies the issue.

I'll look at replacing mine since it drops the gauges down to about 10 before cutting off.

Being a "shade-tree" mechanic and not having access to some of these specs (especially with air conditioning systems since it's ultra regulated and such) is rather cumbersome.

I got those numbers from an EVTM. Very handy. If you don't have one for your cars, you should get them.

[Stealthlead]

Damn, this thread got intense while I was gone! o.o
All I know is my friend who is helping me out is a certified A/C specialist.. its his job and he knew what he was doing/looking for. He told me my system kicking on is exactly what its supposed to do and that the compressor is still in good condition. A big give away was the grease that had leaked out where my high/low clips are. Even I knew this was a gradual leak (although he confirmed it) and not something that cracked over night. In fact, I guess I never realized how much the A/C was actually hurting my idle until I stopped using it which is probably a result of going from a low, to very very low charge. I do distinctly remember him letting out the remaining charge in my system so there WAS a charge, and before letting out the charge, it was attempting to complete cycles. I think he used compressed air to test it in order to find the leak, and then re drained it (I'm obviously not using the A/C in order to prevent further damage ESPECIALLY to the compressor).

Keep in mind I may be explaining this wrong, I'm still very inexperienced with A/C systems :p

Thanks for all the information guys!

~Stealthlead

[86VickyLX]

I do distinctly remember him letting out the remaining charge in my system so there WAS a charge, and before letting out the charge, it was attempting to complete cycles. I think he used compressed air to test it in order to find the leak, and then re drained it (I'm obviously not using the A/C in order to prevent further damage ESPECIALLY to the compressor).

OOOH, I'm telling teh EPA

So it wasn't empty

That's good. At least you know what you need.

[Stealthlead]

OOOH, I'm telling teh EPA

So it wasn't empty

That's good. At least you know what you need.

LOL!! I didn't do it I swear!! There was basically nothing in it anyways >.>

[Crownvicman289]

Ya know all my cars in Japan had sight glasses. I always recharged my systems from a can and had great results. Initially, I would underservice since I couldn't measure the weight of the refridgerant I was putting in, but I found that if you service the system until the sight glass goes clear, then your system is full. Servicing by pressure is wrong, wrong, wrong, wrong, wrong. After servicing until a clear sight glass, I let it sit a day and fired up the A/C with a stone cold engine (on a hot day) and turned the A/C on. With it blowing hot as balls air, pressure was in the 50's. After it ran for a couple minutes, it quickly got itself down to the temperature where the thermocouple would disengage the compressor. With it that cold, the low side pressure had dropped to 25psi which, by the gauge, is a smidge on the low side. Point is, it was easier to be an accurate shadetree A/C mechanic in Japan that it is here since my US cars don't seem to have this sight glass.

[1987cp]

So what exactly is a "sight glass" in the context of A/C service? I wonder if it's something that could be retrofitted. Seems advice I've read always says to charge the system by weight or volume, but that's obvious impossible when topping off a previously working system.