Questions and Answers

Pontiac Sunbird Losing It's Cool Q. Dear Mr. Ciulla: The air conditioner in my 1994 Pontiac Sunbird is having difficulty keeping the car cool. I searched your site for an answer, but couldn't find one. Hope I am not duplicating a previous question. If so, I apologize!! 1994 Pontiac Sunbird 2.0 liter OHC Automatic transmission 109,000 miles Fuel injection ABS brakes, P/S, A/C

I purchased a pressure test meter and thermometer. The thermometer read about 80° after five minutes when inserted in the middle vent with the A/C on maximum cool and the blower on full. I could find no place on the AC under the hood to check the pressure. There was a port with a note that read, "This low side A/C port for factory fill only. Do not use for pressure check."

I added 12 oz of 134a refrigerant at this low side port, and the temperature appeared to improve from 80° to 70°. (Should I have even done so at that port?) Then, about a week later, I added another 12 oz. The temperature at that time appeared to improve to about 63°. However, when I drive the car, the temperature does not drop below 70° in really hot weather (above 85° outside temperature), or below 60° at other times.

My question concerns whether I should have even added the refrigerant, and if it would now be wise to try to add more. (The 134a was specified on the air conditioner.) I have read that no more than two cans should be added.

Is there a place to check the pressure on this vehicle? Should the temperature not be below 60° when exiting the middle vent inside the car? My understanding is that it should be somewhere between 45 and 60°, or at least 40° cooler than the air temperature. When I drop the blower intensity down to its lowest level, the thermometer reading does drop some more, but then, increasing the blower intensity to maximum causes the temperature at the vent to rise again. Is that just because the A/C cannot keep up when it has to push cool air all the way into the car?

Anyway, just curious as what I should try next, and if there is a way to check the A/C pressure.

If you can suggest any answers or next steps to the questions I pose in this e-mail, that would be great!

Thanks. You have a great website!!!
Mike

A. Bottom line is you are low on refridgerant! WHY? You must have a leak somewhere. You can add stuff all day but if it leaks out again you are not saving any money, right? I would have it evacuated and recharged with the corect amount of freon. Also would have U/V dye added to system so someone can find a leak with a black lite.

The temperature rise with the increase of blower motor speed and fall with the lower blower motor speed is normal. All cars do that.