A/C Problem

azazel_18_2 · Post by **azazel_18_2** » Sat May 26, 2007 3:26 am

I have a 2000 Nubira CDX with 95k miles and am having A/C problems. The a/c Compressor will kick on and run but the air never gets cool so I thought I needed R134. I put my gauge set on it and it reads 75 psi on the LOW side!!! I let a little out to try and get the pressure down and as soon as I closed the valve the pressure shot right back up. I drained almost all the R134 out of it to where it had 10 psi. I got a can and as soon and I put a little bit back in the system the pressure shot back up to 75 psi. HELP!! The only thing I hate about this car is trying to get parts. I was thinking maybe the drier needs replaced. Try finding one of those!

TxDAEWOOxT · Post by **TxDAEWOOxT** » Sat May 26, 2007 6:01 am

You may have something wrong with the compressor its self. It may come on and run but may not be pumping(compressing).

Turn off the A/C system and check the pressure. The pressure should be at the highest pressure on the low side while the compressor is off.

Turn the A/C on and check the pressure again, it should drop if the compressor is working right.

As far as the filter/drier. Check the temprature on one side of the filter and see if there is a difference on the other side of the filter. It should be warm on both sides of the filter(freon flowing through smooth). If there is a restriction in the filter it will be cold on one side. A restriction in the filter will act like a thermostatic expantion valve making the freon convert from high pressure liquid to a low pressure gas, thus making it cold.

You can do the same thing all over your system and see if there is a restriction anywhere else.

The only restriction should be a the expantion valve near the evaporator (on the inside of the car).

Mess with it a bit and get me some more info and i will try to help anyway i can.

azazel_18_2 · Post by **azazel_18_2** » Mon May 28, 2007 8:32 pm

First I checked pressure before I turned on the compressor. Low side was 40 and high side was 50. Started car and turned a/c on max and low side went down to 30 while high side stayed the same. I checked the lines and none of them were even a little bit cold and I checked everywhere. What do I need to do? Anybody know? Do I need a new compressor? If so that is sad it only lasted 95k miles.

TxDAEWOOxT · Post by **TxDAEWOOxT** » Tue May 29, 2007 3:53 am

You may be low on freon if the high and low side are reading only 40-50 lbs.

Did the compressor come on when you turned on the A/C? If it did then i would say its a bad compressor.

If it didnt i would say give it some freon and see if it will come on. They have built in pressure switches that will not allow the compressor to burn its self up by running low on freon. The normal running pressure for 134a on a car A/C is about 32-36 lbs on the low side. The high side will depend on the temp outside and weather the condenser fans are running or not. I dont ever look at the high side unless there is a bigger problem.

When the A/C is off the pressure in the system will equalize to about the same. There is no solenoid valve on the lines. There is a solenoid that turns on and off the compressor.

If you turn on the A/C do you here this solenoid close?

I dont want to be the one to condem your compressor without having it right in front of me. I will help anyway i can.

You got some good use out of that compressor. Dont worry its a machine and it can be fixed!!!

azazel_18_2 · Post by **azazel_18_2** » Wed May 30, 2007 3:04 am

My compressor does kick on. You can hear it and I have taken off the inner fender and watched it come on. SOmeone said I could have a clog but I don't think so. None of the lines get even a bit cold at any point in the lines.

MMamdouh · Post by **MMamdouh** » Wed May 30, 2007 8:52 am

could be the stupid valve at the bottom of the compressor... i had full charge and no cold air at all, turned out to be a faulty valve.

MMamdouh

azazel_18_2 · Post by **azazel_18_2** » Thu May 31, 2007 12:01 am

where can I get the valve or do I have to get a new compressor?

TxDAEWOOxT · Post by **TxDAEWOOxT** » Thu May 31, 2007 12:31 am

MMamdouh wrote:could be the stupid valve at the bottom of the compressor... i had full charge and no cold air at all, turned out to be a faulty valve.

MMamdouh

What valve are you talking about?

Is it a expantion valve like this?
http://www.trustmymechanic.com/images/e ... _valve.jpg

azazel_18_2 · Post by **azazel_18_2** » Thu May 31, 2007 3:42 am

I believe he is talking about a pressure relief valve not an expansion valve. I amy be wrong.

TxDAEWOOxT · Post by **TxDAEWOOxT** » Thu May 31, 2007 4:00 am

ok maybe my years of training have been overcome by a automotive A/C. i have never heard of a "pressure relief vavle" on a car A/C. There are not many components on a A/C system in a car.

low pressure switch - will turn the compressor off if it runs low on freon
compressor
expansion valve
condensor coil
evaporator coil
suction accumulator

Those are the main components in an A/C system. I know there are tons of parts that will work with the A/C i.e. solenoid, clutch, full throttle cut out and all that good stuff. As far as the system that actually makes it cold that is what i work with. If any of the other mechanics could chime in and let me know what other parts could go bad in a car A/C i will try to help as much as i can.

mister_g · Post by **mister_g** » Thu May 31, 2007 8:03 am

azazel_18_2 wrote:I believe he is talking about a pressure relief valve not an expansion valve. I amy be wrong.

I think that there is this valve, bolt on compressor.

Daewoo has pressure sensor that converts pressure to voltage...

azazel_18_2 · Post by **azazel_18_2** » Thu May 31, 2007 11:01 pm

Here is a breakdown of the compressor. #19 is a "VALVE-HIGH PRESSURE RELIEF ". I haven't ever heard of the such but it is there. I will probably just replace the compressor with a new one. You can get NEW onces off Ebay for about $275.[/img]

MMamdouh · Post by **MMamdouh** » Sun Jun 03, 2007 7:42 am

TxDAEWOOxT wrote:
MMamdouh wrote:could be the stupid valve at the bottom of the compressor... i had full charge and no cold air at all, turned out to be a faulty valve.

MMamdouh
What valve are you talking about?

Is it a expantion valve like this?
http://www.trustmymechanic.com/images/e ... _valve.jpg

nope... not htis one

look at the diagram at the bottom of the post, the valve i am reffering to is P/N 18... you can see it if you go under the car and look at the compressor, it will be at the bottom of the compressor.

MMamdouh

MMamdouh · Post by **MMamdouh** » Sun Jun 03, 2007 7:47 am

looks like this one:

MMamdouh

mocpac · Post by **mocpac** » Sun Jun 03, 2007 3:50 pm

Try this, remove the heater cable from the panel. Maybe is broke and even if its cool on the panel the car mar hot.