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Q: AC not working properly.

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My Saturn Vue's AC will not blow cold air at idle when it's running in park, stopped at a traffic light or a stop sign. It'll only blow cold when I'm driving or if I rev on the engine while it's in park. I checked psi at low pressure line while engine running in idle with AC turned on max and it reads between 80-85 psi. When the engine is revved the pressure gauge will drop to 45 psi. Fans and compressor seem to be operating normally. Any answers on what the problem could be would be greatly appreciated. Thank You!

My car has 117000 miles.
My car has an automatic transmission.

Your low-pressure reading of 80-85 psi is a bit high. Even with ambient temperatures of 100 degrees, a reading of 50-60psi is normal. A few things can be causing that high reading. First, if the system has been charged recently, it may have been over-charged. Second, a restriction within the A/C system like a partially clogged expansion valve or receiver/dryer. Finally, the car may have a failing A/C compressor. If you need help having these checked, have a mobile technician from YourMechanic inspect your A/C system for a proper diagnosis.

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