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Air Conditioning (A/C) Problem, New Compressor, Doesn't Cool, Please Help!

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jm1080

15+ Year Contributor
640
3
Jun 13, 2006
Boca, Florida
This problem is really annoying...So anyways, my A/C compressor gave out, bad clutch. I bought a re manufactured one and installed with new drier. Installed, vacuumed, recharged, all necessary steps to install A/C. Also added dye to check leaks. Everything was setup fine and was running perfectly. Now once we test A/C, we put at full blast and it cools, but it takes a while to cool (this was at night when we tested).

In the daytime when it is really hot here in FL, lets say car is cold and I turn on A/C it cools fine. Now after driving for a bit and sitting in idle, I turn A/C on and it blows normal temp air, a bit on the cooler side, but not icy cold at all. I leave it on for like 5minutes and still the same, sweating inside the car...Now when driving it gets a bit cooler, but still not as icy cold as it used to be...There are no leaks and pressure is good. What can this be? Im so confused. A/C Techs please help!
 
usually that means you have a leak or the condensor is clogged with grass bugs etc, or it needs to be charged more when you charged it how much did you add
 
Could be a leak, do you see any fluid coming from the connections you were messing with when you replaced any parts?
With the AC running see if any of the pipes are cold or very hot, that would mean you have a clog somewhere.(the hot part)
If your cold pipe going through the firewall isn't ice cold that's the first indication you have a problem.
 
Could be a leak, do you see any fluid coming from the connections you were messing with when you replaced any parts?
With the AC running see if any of the pipes are cold or very hot, that would mean you have a clog somewhere.(the hot part)
If your cold pipe going through the firewall isn't ice cold that's the first indication you have a problem.

Which pipes are you talking about? A/C lines? So right when I turn on the A/C see if the pipes get really hot or really cold?

I don't get why sometimes it runs really cold and sometimes it does not?? Like early this morning it wouldn't cool at all and this evening it was running real cold, so frustrating. Could that indicate a leak, if so how would a leak, cause it to be hot and cold at different times?
 
Oh it gets warmer then goes back to being cold like it should be?

The aluminum tubes I am talking about, they should reach 'operating' temp in under a minute or two.
Your fan and clutch kick on/off as they should? When one of the pipes get hot(=clog or something) it should trigger the high pressure switch and disengage the AC clutch. Same for low pressure.
 
Oh it gets warmer then goes back to being cold like it should be?

The aluminum tubes I am talking about, they should reach 'operating' temp in under a minute or two.
Your fan and clutch kick on/off as they should? When one of the pipes get hot(=clog or something) it should trigger the high pressure switch and disengage the AC clutch. Same for low pressure.

aluminum tubes? hmm not sure which your talking about, Ill try and get a pic and maybe you can pin point me to the right direction.

And yea fans always on and clutch engages all the time when i turn ac on, compressor is new and is working perfectly. It is just that one day it usually when car is cold, it blows ice cold air. Then if car is sitting outside or something in the sun, or after a while from driving it does go cold as well, but not as cold. Then other times lets say just idling outside a store or something it would be blowing not warm air but not cold air, even when having it full blast for like 5-10minutes. It is random...I hate it! especially in this heat! :ohdamn:
 
Ok just an update, I checked the lines with a friend and they were perfect one a bit colder then the other I believe. He said it was normal.

Also I checked out that thread, defiant. I will check the ACCU, but everyone's problem with that is that their A/C compressor doesn't turn on. Well mine turns on and fans go on. Well I have my fans set to all on w/ dsmlink. Also A/C works sometimes and sometimes it doesn't cool as much as before depending on heat condition is what I believe.

I don't know if overheating can make A/C not cool as much, but I' am experiencing overheating problems, my temp in dsmlink is usually 210-226*, 210 just cruising and it can reach 226 or higher if driving for a long time. Now my stock gauge works and it is always sitting in the middle. So I'm not sure if it can be the Coolant Temp Sensor for the ECU, Im guessing it is that because the idle sometimes drop real low like it is about to die, when the car is hot then goes cold for like an hour or so and it is turned on again (which I hear is a symptom). I already changed thermostat and no difference, will be changing radiator with new hoses next week to see if it really is the Temp Sensor. So would overheating be a culprit as well? :banghead:
 
I don't have any additives in the system, will be adding water wetter if radiator w/ new hoses doesn't make a difference. If non of that works, I will buy the coolant temp sensor for the ECU.

Also defiant, I changed out thermostat already and it did nothing. My stock radiator cap isn't leaking, should I upgrade to those 1.4bar or whatever they are caps?

And overheating, well what the ECU reads causes A/C to run warmer?
 
Did you change your expansion valve? That's SOP whenever you replace your compressor especially if you had a bad clutch.
 
Did you change your expansion valve? That's SOP whenever you replace your compressor especially if you had a bad clutch.

Hmm, I don't believe expansion valve was changed. Where exactly is that and what does it look like? Sorry I'm a newbie to A/C :ohdamn:

Just changed out compressor and the drier. And yes I also see bubbles in the sight glass, it green because of the dye though. Changing radiator and all hoses tomorrow.

Also what is the best antifreeze/coolant to use? Any specific brand? My friend told me about specific turbo coolant, which keeps temps real low, not sure which he is talking about though.
 
You will have to take evaporator out for you to gain access to the expansion valve. They are underneath the dash. It's a PITA if you ask me. You have to buy a service manual if it's your first time doing it. Also, you shouldn't see bubbles in the sight glass. If you see bubbles, that means that you are low on refrigerant. Try charging it more until the bubbles disappear. With the expansion valve, they tend to clog especially if the compressor clutch gave out. A lot of the parts retailers won't even honor the warranty on the compressor if you didn't replace your expansion valve and reciever/ drier.
 
Also with the a/c lines, the low side should be cold and the hi side should be hot. Try spraying your condenser with water using a garden hose. Are you still overheating? If so, you might have a clogged radiator. Try flushing it. Try Prestone radiator flush. That works well in my experience. When filling up the system with coolant, make sure that you bleed the system well. Air in the cooling system will cause overheating.
 
Also what is the best antifreeze/coolant to use? Any specific brand? My friend told me about specific turbo coolant, which keeps temps real low, not sure which he is talking about though.
Don't start a new topic in your original thread.

Use Prestone. Get a gallon of 50/50 pre-mix, pour that in, and fill the rest with a gallon of distilled (not "drinking") water from the grocery store.

Back to your AC situation.
 
You will have to take evaporator out for you to gain access to the expansion valve. They are underneath the dash. It's a PITA if you ask me. You have to buy a service manual if it's your first time doing it. Also, you shouldn't see bubbles in the sight glass. If you see bubbles, that means that you are low on refrigerant. Try charging it more until the bubbles disappear. With the expansion valve, they tend to clog especially if the compressor clutch gave out. A lot of the parts retailers won't even honor the warranty on the compressor if you didn't replace your expansion valve and reciever/ drier.

Thanks for your response! Very helpful. I would like to clarify some things. I checked the high pressure and low pressure tubes when car was cold in the morning and let A/C sit on for like 5 minutes. Not sure which is the high or low pressure, but the right line (if your looking straight at the engine bay) was very hot, not hot where you would burn yourself, but hot for the car being cold. The line to the left of it, was warm, not as hot as the right line. Not sure if that is normal.

As for the sight glass, I did not see bubbles, just see green dye in there like a fog.

I'm guessing if one thing isn't working properly such as condenser, expansion valve, or evaporator, the A/C won't work 100%, but where exactly is the expansion valve? I tried searching here and vfaq and no luck. Any way to determine if either or is bad? When I do my radiator I will check the condensor. Thanks again for the help!
 
The easiest way to tell which line is high/low pressure is the size of the lines. The low pressure line should be significantly bigger than the high pressure line.

As far as the expansion valve, don't know where it is but I believe it's the part that transitions the high pressure side to the low pressure side. Basically a valve with a small opening that releases the high pressure into the low pressure. Kinda like this

HIGH < LOW

The (<) is supposed to be the valve. Hope this makes some sense...
 
I found a diagram on the service manual that I downloaded.
 

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thanks for that diagram, very helpful. Seems like a pain to get to though. Well just an update, while changing out the radiator, checked the condenser and it looks perfect like new, surprised. I'm assuming that the expansion valve and evaporator are good as well.

Now I don't mean to change topic, but I'am assuming the reason why A/C does not cool sometimes is because of my overheating. Well I changed out the radiator and old radiator was fine...Still installed new radiator with new hoses and new radiator cap 16psi (from evo) and finished at night, added 80% distilled water and 20% anti-freeze. Drove it hard like 4-5 times in about a 15min drive and guess what! Overheating! Stock temp sensor seems to work as it took a while to stabilize when letting air bubbles out, but dsmlink reads it is overheating...It is making me think it has to be the coolant temp sensor for the ECU, anyone have a clue?! So confused, now this is what I think can be causing my A/C to not function properly when it is really hot. :banghead:
 
Did the overheating problems start after you went fmic ?
Did you check for leaks to see if you have any coolant leaks anywhere ? Bad water pump ? change your coolant temp sensor. Just a few thoughts.
 
The car's overheating problem has nothing to do with your a/c. The caps say L for the low side and H for the high side. The low side, which is the blue line if you have a manifold gauge, should be cold and the red line, which is the high side should be hot. Try spraying the condenser with water using a gaden hose while the a/c is on. See if that helps. Since it's humid there in Florida, you have to vacuum the system very well. A very small amount of moisture in the system will also prevent the a/c to blow cold. Regarding your overheating issue, did you use the stock t-stat? I recomend using a racing t-stat that opens earlier. Try adding Water wetter also. I would also adding more coolant. Like 80% coolant and 20% water.
 
Ok just an update, after I did radiator install, I said I was overheating badly, the next day it was real sunny and took it for a drive (very humid over here). So I went to doc office and a few errands, didn't run car hard. Probably ran car for 30min, car was overheating, like always, I have dsmlink to put CEL on when above like 226 degrees I believe. Anyways CEL went on like always, and the stock gauge went up as well! Never seen it go up before, it always stays in the middle. Well I found out, I forgot to plug in the driver side fan..:ohdamn:

I flushed radiator fluid and added pure distilled water and radiator cleaner to clean out system. I drove it around for about 40-50minutes, sometimes hard. And dsmlink states overheating sometimes (switching on and off the CEL), but stock gauge this time is always stable in the middle. Im guessing ECU sensor must be bad because when fan wasn't working the day before stock gauge went all the way to overheating, which was the first time I ever saw that.

Also 96mitsu, I changed out t-stat to a 170 degree and waterpump is new, changed out all hoses except for the heater ones. I will be flushing radiator again because of the cleaner, and will add water wetter. But why do you say more coolant? Such a huge debate, but people say use more water then coolant if in hotter weather, then I talked to another mechanic and he runs 100% coolant here in FL...Just doesn't make sense to me..:hmm:
 
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