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AC Blows Warm when I am at a Light


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A timeless question. Since I swapped out my AC compressor it will not blow cold air when I am just idling. When I am cruising down the highway its the artic blast. I filled it myself with the stuff off the shelf at Walmart. What is my problem?

 

I don't know what your problem is...

 

...however, you cannot properly charge an AC system without some expensive equipment, namely first off a high quality vacuum pump. The system must be evacuated as completely as possible before charging with refrigerant and oil.

 

Simply adding refrigerant to a system that has atmospheric moisture will not give you an adequately working system. Plus, the mixture of the moisture from the air and the refrigerant will create an acidic mixture that wille at away your compressor seals.

 

It is ususally not worth it for a person to invest in the vacuum pump, the gauges, the fittings, for a one time recharge, plus there is a big learning curve to doing it well.

 

It's best if you take it to a shop. They will charge $50-$100 for a evac-recharge, and point out any leaks you may need to fix.

 

There are many threads here about Subaru AC.

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you probably overfiled it. If you used the same refrigerant you don't really NEED to vacuum the system. It is alot more difficult to spin hte ac when its overfilled so the clutch engages then just disengages when it feels it is to difficult and putting to much of a load on it. But i guess when it is reving higher it will keep it engaged.

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I disagree :-p . The system was opened, and as a licensed AC tech, with (i am going to assume) a used compressor, he needs to evacuate it.

 

I am curious, how long did you have the dead ac compressor in the car, and how long was the system open for.

 

 

nipper

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I recently upgraded my '91 LS to R134a. What should the pressure be? My system was partially charged with R12 so the system wasn't exposed to atmosphere. Should the pressure specs listed on the compressor be used when changing to R134?

 

The A/C does eventually get cold but it seems like it should be colder. I work in a tractor trailer garage with refrigerated trailers and our A/C tech (30+ years experience) thinks that the freon pressure seems to be low based on watching my A/C being operated, but he doesn't have equipment to diagnose my car correctly.

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I put the belts on tight, no method to that madness. The AC system was open for a week before I swapped it out and completed the job. I just filled her up I did not do a evac.
How about the fans? When stopped, are the fans coming on when the compressor engages? If not, it might explain why it works when you're cruising but blows warm when you're stopped.
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I recently upgraded my '91 LS to R134a. What should the pressure be? My system was partially charged with R12 so the system wasn't exposed to atmosphere. Should the pressure specs listed on the compressor be used when changing to R134?

 

The A/C does eventually get cold but it seems like it should be colder. I work in a tractor trailer garage with refrigerated trailers and our A/C tech (30+ years experience) thinks that the freon pressure seems to be low based on watching my A/C being operated, but he doesn't have equipment to diagnose my car correctly.

 

All you need is a gauge set and a thermometer.

So your running a mixed system?

 

nipper

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Here is the deal, I put her in park on the driveway with the AC on. I opened the hood and here is what I saw. The 2 front fans on along with the AC compressor. What I did notice was this, my altanator belt is spinning just fine. My AC compressor belt is bouncing and jumping around. This may be my problem.......

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Here is the deal, I put her in park on the driveway with the AC on. I opened the hood and here is what I saw. The 2 front fans on along with the AC compressor. What I did notice was this, my altanator belt is spinning just fine. My AC compressor belt is bouncing and jumping around. This may be my problem.......

 

:rolleyes:

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Then you can use a sert of charts ( google) to figure out what pressure your running by what temp your putting out. Better off using gauges though.

 

nipper

 

I went back to the mechanic that retrofitted my system. They checked the pressure and said I had the required two pounds of freon. They checked for leaks and found nothing. They added a dye into my system so that if any leaks develop over time, it will show up.

 

They inserted a thermometer into my vent and measured 60 degrees. I have the rare digital climate control unit that won't allow the temperature selected to go below 65. This system also regulates fresh air/recirculation automatically. There is a button marked "recirc" but if the unit wants fresh air, it will override the button pushed after 10 minutes. I also can't determine air flow direction. It allows me to select the temperature and that's about it. I can defrost the windshield, select low or high fan speed and learn the outside temp. It basically says "you tell me what temp you want and I'll deal with everything else".

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