Input needed - Air conditioning

[Durania]

I am leaving the office this evening about to head on a weekend trip and I get to the car (05 STi) and it's close to 80 here. I attempt to turn the AC on and nothing happens. I immediately go into diagnostic mode in my brain trying to figure out this one out. I determine that the compressor is not kicking on, nor is the fans. I get home and use the last remnants of the 134a I had left from when I recharged the system on my RS last year. I put some in and manage to get the compressor to kick on along with the fans but still don't get cold air out of the vents. I talked to my buddy who had the same problem with his 03 WRX and he said it was a 0.30 o-ring that was causing his leak.

 

Any thoughts?

[Fairtax4me]

He's probably right. You have a slow leak somewhere and your refrigerant is escaping them system. The trick is to find the leak. If you have a UV light you can poke around under the hood one evening looking for bright yellow spots where the oil from the system will have leaked out with the refrigerant. Be sure to wear UV proof glasses though so you don't burn your retinas.

[Durania]

What I figured.

 

Thanks man.

[ScottG]

You can often spot an AC leak with the naked eye. Leaks most often occur at the joints - where the hoses bolt up to the compressor, where the hoses connect to the condensor(in front of the radiator), or at the connections to the evaporator. Leaks may also occur at the connections to the filter/dryer.

 

Look for an an accumulation of oily dirt. Almost always, refrigerant oil leaks out along with the R-134. You might try tightening the bolts wherever you find that oily dirt. That may stop your leak.

 

I wouldn't just add more refrigerant. It would be best to put a good vacuum on the system (after you've checked all the connections), for about 45 minutes. The purpose of this is to make sure that you draw any moisture out of the system. If you vacuum for 45 minutes then shut off the vacuum pump for ten or 15 minutes, you'll know in short order if there is a still a leak. Normally. yhe vacuum pump will pull about 28 or 9 inches of mercury. If you slowly see the vacuum dropping at the low pressure gauge, you can be pretty certain that you still have a leak So you'll need a set of AC gauges to do the job correctly. Most new gen Subarus take right at 2 cans worth of R-134. On an 80 degree day, you should see somewhere around 25 to 32 lbs on the low side and around 225 to 250 lbs on the high side. If you have pressures higher than this & there's still not much cooling, the condensor may be plugged up or the compressor pressure is off (possible internal compressor leak, or you have overcharged the system). I know this from experience, have overcharged a few systems in my life.

 

When everything is working properly, you should be able to wrap the fingers of your right hand around the suction (low pressure) line near the compressor and the fingers of your left hand around the suction line near the evaprorator at the firewall and the temperatures at each hand shold feel about the same.

You just want to get them to approximate each other. You'll go nuts bleeding & pressurizing the system trying to get them exactly the same. (I know this because I've done it & gotten the T-shirt for the most times to have partially bled & filled an AC system trying to make it perfect.)

 

If the system is all original, you may want to flush it & install a new filter dryer prior to filling the system. If you flush, you will have to replace the refrigerant oil (PAG type), that you flushed out.

 

By the way, I have had very good luck with a refrigerant called Arctic Freeze, an ultra synthetic (whatever that might be) refrigerant that contains advanced leak sealer, along wth moisture & acid eliminator. The can says ''Colder air up to 50% faster". Another can of the stuff said that it was 18% colder than straight R-134. Can't vouch for any of the figures or claims, but the stuff is VERY cold.......and we get some really HOT days here in central Virginia. Arctic Freeze is available at most auto parts places, and it costs about double the price of regular R-134.

 

Let us know how any repairs go that you might make on your AC system. Best of luck!

 

ScottG

[Durania]

Got the car fixed today. There is a local performance car shop called European Auto Garage in Knoxville. I had lost a lot of faith in the service department at my local Subaru dealer so I figured I would give these guys a shot. Figured that the turbo 911 guys trust this place for major repairs, so can I. Good friend is also the service manager.

 

The fix: the o-ring where the line meets the compressor was nowhere to be found. 2 hours and $120 later my AC is now back again. By the way, it didn't get out of the 40's here today.

[bheinen74]

glad it was oring.

When they pressure check they usually hook the line up at the low pressure fitting to test leak down etc. If the oring on the valve where they check also leak, it will never show up, till after they fix the oring leak, and it will eventually leak out again. Always best to replace everything on the fittings.

 

"you can install a brand new tire on a brand new rim, and trickl soapy water around front and back beads, and it might not leak, but you have to test the valve too... and AC places cant test it there where they hook up the equipment, if that valve leaks it wont be detected and you will lose refridgerant over time,

DONT go to Waterloo Iowa Subaru dealer, they cannot properly replace all orings, even though they were asked to do so and paid to do so......

Edited March 29, 2011 by bheinen74

[gregB]

My 97 Legacy GT has no AC, looks like a bad o-ring. The larger one on the low side hose to the compressor. Its pretty stiff and smashed, I do not know if I can size it correctly. Does anyone have the part number for both the o-rings on the compressor? Or the standard o-ring size number?

 

Thanks for any help

 

Greg

[NoahDL88]

 

I wouldn't just add more refrigerant.

 

If you take nothing else QFT

 

 

Get it fixed right, adding refigerant will not fix the problem, it will only fix the symptom. Get it sniffed, have the leak fixed and then have it sucked down and refilled or any moisture that gets in from having the lines open will toast your compressor.