[1fast72]

I have an 05 Impala with the 3.4L. The A/C is not blowing cold. I have checked all the relays and fuses and all are good. This system is different from others I have worked on b/c it does not have a low pressure switch or clutch cycling switch so I have no way of cycling the compressor that I know of. I bought some freon from the parts store with a gauge and when I hooked it up it went in to the "Red Danger" area at about 90psi. I am sure that I am on the low side. So my question is will too much freon cause the compressor not to cycle or is there a clog in the system. There is not an orifice tube like in other R134a systems. Any help would be appreciated.

 

[wedebrook]

when you run the a/c or the defrost to the windshield is there an audible "buzzing" noise that gets more prevalent as you go to higher fan speeds?

 

[77Impala]

The gage will only hook to the low pressure side. If the compressor is not running then a reading of 90 to 110 is fine for all it means is the system is charged and balanced between the high and low pressure lines. At this moment the problem is not due to low freon level.

 

[wedebrook]

my vote is a failing compressor.

 

[Guest]

If your temperature gauge is reading zero it will also not allow the ac to work see the post on car still running

 

[1fast72]

Thanks peeps, I was afraid that the compressor is bad. Bought the car as a repo and who knows whats wrong.

Extremetint- can you give me a little more on the post you are referring to. Like a link thread title.

Edit: Ok had a brain fart and wasnt sure what a LIM gasket is..lol Now Are you talking about the inside temp gauge or what. The temp on the gauge shows normal temp. Or the sensor for the PCM reading wrong?

 

[77Impala]

PCM temp sensor is what he is referring to.

 

[1fast72]

Well I might try that since it is the cheapest between the compressor and the gasket kit. I didn't know that the sensor reading 0 could cause this.

 

[wedebrook]

LIM = Lower Intake Manifold.

very very common for these to fail, since when they were put in at the factory, GM used gaskets that were not all that compatible with DEXCOOL. it ends up eating at the gaskets and causing coolant to get in your oil or oil/coolant to seep out of the engine. either way, its bad business. you can do the gaskets yourself, if you have a day or two to work on it. or you can pay a metric sh*tload of money to a mechanic to do the work for you, its up to you. i will look around for the write up on how to do this for you.

 

[wedebrook]

heres the link: [ame]http://www.grandamgt.com/forum/showthread.php?t=68087[/ame]

keep in mind, although they will be extremely similar, your engine will just be a little different, since this write up is for a grand am gt. but this is what i used to do mine.

 

[Guest]

This is typical it usually means your temperature is reading 0 and you need to change your thermostat my did it till i changed the thermostat, A temp fix until you change it is to go under the hood and find the 25 watt mini fuse marked pcm and pull it then put it back that will stop the fans but your car will start hard the fist time after to relearn pcm. Mine would do the same thing if the temp on dash says 0 then the ac did not work and the electric fans run constant.

 

[77Impala]

Very good find there Wedebrook. The job is not really hard, but will take around 5-6 hours to do. On a 98 Olds Cutlass 3100 V-6 I was able to leave the thermostat in and just pull the radiator hose. That saved time and a gasket. (If t-stat is older than 2 years it would be highly recommend to go ahead and change it while you have everything open that far.)

 

[1fast72]

Well the fans don't run without the engine on. Just the AC compressor doesn't come on. All of the work will be done by me since I don't have the money and don't trust other people to work on my cars. The temp gauge reads between 140 and 200. It will fluctuate slightly but not bad. I did have to put on a waterpump when I bought it. I will try the PCM fuse and see if the AC will run for a minute. Do you think the temp sensor or thermostat is the cause of the AC problem? The clutch on the compressor is free and moves with the engine off. Keep in mind that the engine will rev up when the switch is turned on. Also the fans do not come on when the switch is on.