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A/C stopped blowing cold, not sure compressor is running at all

Tiny
KIWASABI1
  • MEMBER
  • 2001 MITSUBISHI ECLIPSE
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 207,000 MILES
Well, it seems my car problems aren't over just yet. Today on a fairly long drive I noticed my A/C wasn't blowing any colder than the fan. This was strange because it wasn't particularly warm out, probably 75-80 degrees Fahrenheit. It's late and dark so I haven't had a chance to check to see if the compressor is spinning at all. But I noticed that when I turn the A/C or defogger on, there does not appear to be an extra load on the engine and the RPM's don't raise from the IAC. The RPM's just hold steady. At first I figured I just needed more refrigerant since the car is 20 years old and has never been recharged with R-134A. But now that I notice the RPM's no longer adjusting while idling and turning on the A/C, I suspect the A/C compressor or clutch. What do you guys think?

BTW I've been having a very slight overheating issue cropping up while idling or slow moving driving with lots of stops and starts. The thermostat will hover slightly above halfway, then go back down eventually as the fan kicks on I guess. After this happened, the gauge is now filling up a lot more in these circumstances to more like 75%, then coming back down eventually. My question is, does my A/C compressor pulley also run my water pump, and thus the issues could be related? My experience here is I had an A/C compressor go out on my old Saturn years ago (which had lots of noise when the A/C compressor was on BTW, which my current car doesn't have). When it finally stopped working completely, I lost power steering and my car started overheating because the A/C compressor belt ran the power steering and water pump. So I'm curious if they're connected in my car as well.

I'll reiterate here that there are no loud noises, it seems now that the A/C compressor is not engaging at all. I will have to check it and report back tomorrow whether it's spinning or not.
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Saturday, May 30th, 2020 AT 11:02 PM

51 Replies

Tiny
KIWASABI1
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  • 197 POSTS
Probably just disregard the second paragraph. I seem to have mixed up when my alternator went bad with when my AC compressor went bad on my Saturn. Obviously the AC Compressor isn't spinning when it isn't on, so it's not driving the water pump and power steering. Forgive me as this was 16 years ago. For the overheating issue I suspect water pump or thermostat, since the radiator is 9 months old and there are no coolant leaks or white smoke from burning fluid.
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Sunday, May 31st, 2020 AT 3:06 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Good morning,

Do you have a set of gauges to give me the high and low side readings of the system?

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Do you have a voltmeter or test light to do some testing? I want to see about testing power to the compressor.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Roy
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Sunday, May 31st, 2020 AT 3:56 AM
Tiny
KIWASABI1
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  • 197 POSTS
I don't have the A/C pressure gauges. I can borrow a multi-meter. Question: If the A/C compressor/clutch aren't spinning at all, that eliminates the refrigerant as the issue doesn't it? And if the electrical connector tests fine then it's definitely the compressor?

Stupid question, but any chance I can whack it with a hammer like you'd do with a starter and get it moving again? Or any other hack tricks to try like that before replacing anything?
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Sunday, May 31st, 2020 AT 9:06 AM
Tiny
ASEMASTER6371
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Low or no refrigerant will cause this issue. That's why I need to know the pressures.

There will be no voltage to the compressor unless proper Freon is present. We also need to test for proper voltages to all the components.

Roy
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Sunday, May 31st, 2020 AT 9:14 AM
Tiny
KIWASABI1
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Really? Then I'm buying the recharge kit with the gauge on it and going to test the r134a level. I suspected the refrigerant from the start. But since the compressor stopped kicking on at all I presumed a more serious problem. I apologize for being such a hack mechanic. But I've heard always start with the simple things. Being out of refrigerant after 20 years makes the most sense to me, especially since I think I noticed a gradual decrease in cooling ability over the past month or two.
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Sunday, May 31st, 2020 AT 9:20 AM
Tiny
ASEMASTER6371
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I understand.

Keep me updated with the results.

Roy
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Sunday, May 31st, 2020 AT 9:36 AM
Tiny
KIWASABI1
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So today I went to recharge the A/C system, and noticed a broken wire connected to the A/C Compressor (see attached pictures). I believe this is the Refrigerant Temperature Switch according to the repair manual. It's a one wire connector that plugs into the A/C Compressor. There is a separate 2-wire connector which must be power and ground. So this must be the signal wire I assume. Anyway, from the help of a friend, we tinned up both sides of the wire, soldered it back together, added a little duct tape, and the compressor started working again! So that's the solution to this question.

Since I already bought the R-134A recharge kit, I went ahead and did that too since it was a little low as well. I'm a little paranoid that I overfilled it because the gauge is jumping around a lot. I realize it's supposed to read high when the compressor is off, and gives an accurate reading when the compressor is on. But I was getting varying readings while the compressor was running too. Does it take a while for the fluid to circulate or something before it reads accurately? It was reading as high as the yellow area of the gauge (50-60 PSI) while running, and finally settled back around 35-40 (the green area is 30-50 PSI). I'm going to recheck this again in a day or two and see what it says then. I want to be sure I did not overfill it, and thus could cause damage to the compressor.
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Wednesday, June 3rd, 2020 AT 5:18 PM
Tiny
ASEMASTER6371
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The high side reading should be 2 times ambient temperature plus 15%.

The low side should be 25039 pounds, rock solid. It should not vary at all.

Roy
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Wednesday, June 3rd, 2020 AT 5:26 PM
Tiny
KIWASABI1
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Low side is what the kit has me check and plug into. The gauge goes from 0-150 PSI, which 30-50 PSI being green, 50-60 being yellow, and 60-150 being red.

One thing I forgot to do was have recirculate activated, which I know drops the reading further. I've noticed my compressor is kicking on and back off a lot while idling, I notice the RPM's going up and down from the IAC. When I'm driving, sometimes the A/C is blowing very cold, other times it's kinda warm. So something is still not quite right here.
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Wednesday, June 3rd, 2020 AT 5:47 PM
Tiny
ASEMASTER6371
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What is the reading on the gauge when the AC is operating?

Roy
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Wednesday, June 3rd, 2020 AT 5:55 PM
Tiny
KIWASABI1
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See attached video. This is with the A/C set to maximum with recirculate "on". When the compressor is off, it's at 60 PSI. When it turns on, it's around 50. Which evidently is about right on an 80-90 degree day, you're supposed to be at about 45-55. But I suppose my problem is how the compressor is constantly cutting off and on. When it's off and the reading is at 60 (which as you see, is most of the time) it is blowing warm air. When I first turned the car on and it wasn't as heated up, the A/C was blowing very cold and staying on. Once the car got hotter, the compressor constantly cuts out like you see in the video. It would seem there's another problem now unless I'm missing something.
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Wednesday, June 3rd, 2020 AT 6:31 PM
Tiny
KIWASABI1
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Found this comment when digging around. Which 50 psi seems to be where i'm sitting at. So it would seem it's not overcharged. But since I can't verify the high side, difficult to say.

" The CAN is done for safety and it's only at 50 psig. So "normal" people can't get blown up or sue them for damages. I have tried it and tested and it's always neutralized /balanced itself out at 50 psig. Yes, I have tried to overfilled the system, but it won't allow me to do so because there is a limit and balanced due to the pressure in the can itself!"
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Wednesday, June 3rd, 2020 AT 6:50 PM
Tiny
KIWASABI1
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I guess I'll need to get the high side gauge to find out what's going on for sure. Probably going to have my mechanic run the test unless you've have any other suggestions. From doing some reading, it's either undercharged or overcharged most likely.
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Wednesday, June 3rd, 2020 AT 7:31 PM
Tiny
KIWASABI1
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Doing some more reading, sounds like I may have added too much air to the system and need to bleed it.
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Wednesday, June 3rd, 2020 AT 8:30 PM
Tiny
KIWASABI1
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Just realized my manual says 15 ounces of refrigerant. Somewhere online said 21 ounces for my car. It wasn't totally empty, and I probably put in 3/4 of the bottle. So I'm going to have to bleed some out.
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Wednesday, June 3rd, 2020 AT 8:41 PM
Tiny
KIWASABI1
  • MEMBER
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I just did a quick search through the repair manual for PSI and found this that I've screen shot. If I'm reading this correctly, the low side pressure should only be 22-26 PSI when it's 95 degrees outside. When I first put the gauge on, it was reading about 34 PSI or so. I figured, that's on the low side of the green area (30-50), plus when it's hot you're supposed to adjust more like 45-55 I read. I really wish I just left it alone now. Gonna bring it to my mechanic I guess. Otherwise I'm literally bleeding out R-134A onto a towel, which is illegal I've heard.
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Wednesday, June 3rd, 2020 AT 11:51 PM
Tiny
ASEMASTER6371
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Okay, the low side is not dependent on the temperature at all. When running, it should be 25-30 only. If it is higher, the expansion valve is allowing too much Freon into the evaporator.

The gauge you are using has those readings only for adding Freon. They are not indicators for the level at all. Do not think that the reading tells you anything but that you have pressure on the low side.

Roy
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Thursday, June 4th, 2020 AT 3:31 AM
Tiny
KIWASABI1
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Is there any way I can safely release the excess refrigerant until the car stops short cycling?
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Thursday, June 4th, 2020 AT 3:42 AM
Tiny
ASEMASTER6371
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No, you need a recovery machine to remove all the Freon, vacuum the system down for about 45 minutes and charge the exact amount of Freon required.

Roy
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Thursday, June 4th, 2020 AT 3:50 AM
Tiny
KIWASABI1
  • MEMBER
  • 197 POSTS
We vacuumed it out down to 25 PSI. Now the compressor stays on. Perhaps not as cold as I'd like, but it's working. And as I posted above, the absolute MAX the repair manual calls for is 28 PSI when it's 105 degrees out. Erring on the side of caution with refrigerant from now on. Thanks for the help.
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Thursday, June 4th, 2020 AT 4:12 PM

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