# 2005 Chevy malibu A/C problem



## wolfen1086

Ok guys I need some help here, We have a 2005 Chevy Malibu LT, With a 3.5L auto, FULL power, and I mean FULL power, sweet car, only thing I suk at A/C systems, and the car was starting to blow a little warmer than it did last year, so I'm thinking, since its a R134a system I can fix it myself, well, here the what happened.
First, A/C working, but not blowing as cold as it should, 
Second Added a can of that R134A from Advance with the gage on top, followed the directions on the can for the temp I added to the proper psi as far as I know.
Third compressor turns on and off about every three seconds, so I think ok I over charged it.
Fourth, removed some R134 from the system and compressor starts working constant, 
Fifth, wife drives it to work today, compressor is turning on and off so fast the A/C cooling fan can't keep up and makes the eng temp go higher than normal.
Any Auto A/C guru's out there? I learned a long time ago that I suk at A/C, but I had to try one more time, now I'm done trying cause I don't want to screw the engine or A/C system up on this car.
Any help would be greatly appreciated.


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## Wrench97

It may still be overcharged, at faster RPM's the high side will get higher and since pressure and temp are static with Refrigeration (the higher the Pressure the higher the temp and the lower the pressure the lower the temp), I hate those cans with only one gauge since you have watch both HI side and Low side if attempting to charge without evacuating and charging by weight.(The correct way)

Any chance you can get a set of gauges on it to see what the high side is?
Keep it under 300PSI before the fan starts and 150-170 with the fans running.


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## wolfen1086

Thanks Wrench, I'll keep this thread handy until I can buy a complete set of gages, and tell you whats what, but in the mean time will it be ok if the A/C is NOT used? Or shoudl I dump everything and just run with windows down


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## Wrench97

IF the A/C is not used you should be Ok, but remember it also comes on with the defrosters so you may want to unplug the compressor clutch.


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## Raylo

First, it is normal for the a/c clutch to cycle under load a/c loads and low ambient temps but rapid cycling can also be a symptom of low charge. In fact as you charge a system up from zero the compressor won't cycle on until it hits the low pressure limit, then cycles rapidly as charge builds, then the run time extends longer and longer as full charge is reached. But the clutch will still cycle under low a/c load at full charge. These systems are called CCOT (Cycling compressor orifice tube) for a reason.

Second, I also recommend not monkeying around with your charge based on subjective feeling about how cool the air is. Get a little hvac thermomometer and stick it in a central vent and drive around letting the a/c get to operating conditions and observe the temps. Not sure there is a definitive number but it should get down to the low 40s or so.

Third, it is almost impossible to determine charge state, even with a set of gages. The static system pressures varies with ambient temp according to the r-134a chart and the operating high and low side pressures key off that. So all this varies a lot with changes in ambient temp. The only truly reliable way to determine proper charge is to evacuate and charge the exact amout of R-134a on the label plate for your system whic is a surprisingly low number.

But if the system was truly underperfoming before you charged it you have a leak. Rent/borrow/buy a leak checker and have a look.


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## Wrench97

It'll also rapidly cycle if over charged and building too much head pressure, to prevent compressor damage and blowing a line or condenser. R134a doesn't like to be overcharged


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## wolfen1086

It has to be an overcharge condition, I let a little more out today, the compressor came on and remained on through the entire 10 mile test trip I did with a digital multimeter that reads air temp, it was 80 deg F, and I had 48deg F out of the center dash vent, I don;t know if I hit the spot or not we'll see after tomorrow, I'm still going to have a pro lok at it, but in the mean time I need it to work cause I can't reach the compressor plug on the compressor


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## Wrench97

And if it doesn't work the wife will take away computer privileges until it does?

48 is a little warm I would be tempted to let a little more out, have you checked the cabin air filter?


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## wolfen1086

wrench97 said:


> And if it doesn't work the wife will take away computer privileges until it does?
> 
> 48 is a little warm I would be tempted to let a little more out, have you checked the cabin air filter?


Nope she won't and cant, I'm the administrator  I can't get on neither can she 

cabin filter was replaced last month when I replaced the air and fuel filter, I replace ALL filters at the same time on my vehicles, I know it seems like a little early for some, but its a good way to remember.
It seems to be working as of this afternoon, we went to wal mart and nothing happened, the compressor stayed on, don't know how cold it was my temp side on the multimeter bit the dust this morning at work 
So i think I'll leave it alone until I an find the gages, and can tell for sure.
But I think I have found a leak at the low pressure schrader valve, it was bubbling the yellow dye after I removed the gage yesterday and I wiped it out with a Q tip, and today Its yellow under the cap again.


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## Midnight Tech

Wolfen, do you have a tool to tighten the Scrader valve? Try tightening it VERY slightly.


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## wolfen1086

I have one for bicycles, and several for tires, I used to work at Tread Quarters as the tire installer, so I bought a few different ones, I'll try one here soon and see if it works. I haven't been able to find a set of gages for less than 89* dollars here locally, so I won;t be bale to get my own gages, but I did pass a garage that had a free A/C check sign, so tomorrow its going up there:

I drove it again today wife said it surged on the way home so I wanted to see what was what and she started out warm, then got colder as we went down the road. I am thinking about maybe letting some more R134 out, but I'm also scared that I'll screw up the unit if I do.
And this is the first car I've ever owned that had a working Air conditioner, I
d lie to keep it that way cause my wife ha slight asthma and cool air helps her a LOT.


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## Wrench97

Same tool that tightens them in tires will do.


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## wolfen1086

Thats good thanks Wrench, I have had that tool for bikes sine I was 16
Didn't take it for the A/C check yet, been working on a Jeep Cherokee all day replacing believe it or not the A/C compressor LOL


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## Wrench97

Of course when it rains it pours.................


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## wolfen1086

It poured alright, the Cherokee owner poured 40 dollars into my pocket just to replace a compressor and dryer, I really gotta start doing more than just brakes on other peoples vars, last year I got $1000 just to install a 318 in a 1976 Fury.


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## Wrench97

You work too cheap, I did a condenser, dryer, evac/charge this morning for $125, Easy one on a Peterbuilt, Condenser was $415, Dryer $43, $12 for Freon $4 for oil, $600 Pete dealer wanted $1500


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## wolfen1086

Yea I work cheap, I do brakes for $30 a wheel, plus you bring me whatever brakes you want installed, but the reason I do hat is to wake people around here up to the fact that the ASE certified mechanics aren't any better than I am, just paid more.

Oh today it was 93deg F and the cars A/C blew kinda cool, so maybe tomorrow I'm taking it to a tune up place that has a sign saying "free A/C check"


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## Wrench97

That's almost the same as free estimate


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## wolfen1086

Yea I know  But if I went any higher in price the City would start looking my way. and charge me for working on things on my own property


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## tom99S104x4

wolfen1086 said:


> I have one for bicycles, and several for tires, I used to work at Tread Quarters as the tire installer, so I bought a few different ones, I'll try one here soon and see if it works. I haven't been able to find a set of gages for less than 89* dollars here locally, so I won;t be bale to get my own gages, but I did pass a garage that had a free A/C check sign, so tomorrow its going up there:
> 
> I drove it again today wife said it surged on the way home so I wanted to see what was what and she started out warm, then got colder as we went down the road. I am thinking about maybe letting some more R134 out, but I'm also scared that I'll screw up the unit if I do.
> And this is the first car I've ever owned that had a working Air conditioner, I
> d lie to keep it that way cause my wife ha slight asthma and cool air helps her a LOT.


Hi wolfen, harborfrieght.com has a set of a/c manifold gages on sale for 29.99 today. i bought the same set for 49.99 a few months ago from them. there not of the higher quality but work fine for the do it yourselfer. hope this helps you out, Tom


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## wolfen1086

Really? I gotta go over to Norfolk and see if they have any.

Oh guys I let a little more out and the temp dropped from 50 deg output to 48 deg output at 80 deg OAT

And I talked to teh guy who does my house A/C, he pushed the valve in while the engine was running and said there was liquid in there, so he suggests releasing more to see if it gets colder, apparently there isn't supposed to bu liquid on the low pressure side. Which makes me believe I read the instructions wrong and turned the can the wrong way and let liquid into the system.


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## Wrench97

The system will have liquid in it, the line coming out of the condenser to the accumulator is known as the liquid line, that is also the high side, the low side should be gas to be compressed and turned back into liquid in the condenser.

He may have also seen oil(which is normal), liquid in the low side at those temps is a little hard to believe.

Can upside down puts liquid in, but if done this way may damage the valves in the compressor(liquid won't compress so something has to give), charging should be done with the can right side up so only gas comes out. I do sometimes when in a hurry on a recharge and to keep the bottle pressure up use liquid when pre-charging(before starting or turning on) to get more into the system faster.


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## tom99S104x4

wolfen1086 said:


> Really? I gotta go over to Norfolk and see if they have any.
> 
> Oh guys I let a little more out and the temp dropped from 50 deg output to 48 deg output at 80 deg OAT
> 
> And I talked to teh guy who does my house A/C, he pushed the valve in while the engine was running and said there was liquid in there, so he suggests releasing more to see if it gets colder, apparently there isn't supposed to bu liquid on the low pressure side. Which makes me believe I read the instructions wrong and turned the can the wrong way and let liquid into the system.


hi wolfen, when you go to see if harbor feight has the gage set, also look at the air vacuum pump for $12.99. you hook it up to your air compressor and auto a/c to vacuum out the moisture in your a/c system. this way you can vacuum out your system and refill it. regards Tom


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## wolfen1086

wrench97 said:


> The system will have liquid in it, the line coming out of the condenser to the accumulator is known as the liquid line, that is also the high side, the low side should be gas to be compressed and turned back into liquid in the condenser.
> 
> He may have also seen oil(which is normal), liquid in the low side at those temps is a little hard to believe.
> 
> Can upside down puts liquid in, but if done this way may damage the valves in the compressor(liquid won't compress so something has to give), charging should be done with the can right side up so only gas comes out. I do sometimes when in a hurry on a recharge and to keep the bottle pressure up use liquid when pre-charging(before starting or turning on) to get more into the system faster.


God I hope I didn't screw the system totally up then, the can I had said to rotate it from 12 to 3 o'clock and shake it every three seconds so thats what I did with the engine running, so if I put liquid in there that would explain the whole problem 



tom99S104x4 said:


> hi wolfen, when you go to see if harbor feight has the gage set, also look at the air vacuum pump for $12.99. you hook it up to your air compressor and auto a/c to vacuum out the moisture in your a/c system. this way you can vacuum out your system and refill it. regards Tom


Thanks, man, I already have a vacuum pump, my father in law died of Enphazima and he had a vacuum pump to vac his treck out and I modified that after he died to suck brake systems out. it'll pull a 29 inch vacuum on my gage, only problem is it take s15 inutes to do it LOL


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## Wrench97

As long as it changed from Liquid to Gas before it got to the compressor your good, those little cans probably have a small enough opening at the valve to cause a pressure drop(orifice effect) and change over.

15 minutes is good, I've seen those air operated pumps take close to an hour to pull them down, you need to leave them run for at least 1/2 hour after getting to 29 inches.


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## wolfen1086

Good cause I really hate buying compressors.

And I hope 15 minutes is a good time cause guess what I'm gonna try tomorrow,


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## Wrench97

I'm almost afraid to ask '

You're not evacing the Mabliu are you?


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## wolfen1086

wrench97 said:


> I'm almost afraid to ask '
> 
> You're not evacing the Mabliu are you?


LMAO I figured you would be, no I'm not gonna evac it, but I am gonna put my multimeter back in the vent and set it to temp and see when happens if I hold the lever down for 1 second at a time until I get a temp change, if it goes lower I'm good, if it gets warmer, I'm too low


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## Wrench97

Sounds like a plan, and by the way buying the compressor is the easy part on most cars I see today, installing them is the hard part.


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## wolfen1086

Well I was going to do that today, but instead I spent all day doing the following, 91) had top replace the wifes Black berry due to a equipment malfunction (2) trade my printer in for a new one using the extended service play/insurance  ( hp F4480) and then I had to go help my asst from work with his truck ( 2005 Chevy C1500), He said the brakes went out, what I found was a bad vacuum booster, and 2 leaky rear calipers (4 wheel disk)
Gonna try the A/C thing tomorrow.


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## Wrench97

At least you had a productive day today, even if you didn't fix the wife's A/C.


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## wolfen1086

Yep it was productive alright, got to eat the nice lunch his daughter made too, shes a pretty good cook for a 12 year old


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