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Quick ac question

Quick ac question

Postby darkmj16 [OP] » Jun 09 2021, 6:06pm

So it seemed like my cooling fans were staying on for a long time and being loud. But engine temp is normal. And the air seems like it use to be colder. 2009 silverado 5.3.

Took pressure readings. It is 78 degrees. Humidity between 50-75% my best guess. And the readings are 50 low side 200 high side. And holding pretty steady. From what i find online low side seems high. Is that correct?
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Re: Quick ac question

Postby 00pooterSS » Jun 09 2021, 7:31pm

That seems about right. Your low side, when the freon charge is correct, will generally follow the temp inside the cabin of the vehicle.

If you run the fan on low the low side will come down, if you run the fan on high it'll go up (pulls more heat out of the air on high increasing the temp in the a/c lines and causing pressure to rise).

Be a good idea to have the freon measured/checked/serviced just to be sure but it sounds relatively correct.

If you let the ac run longer and the inside of the car cool more it may come down to 40 or so.

Running it in direct sunlight or shade can affect inside temp/how much heat the a/c system pulls in and affects low side as well. Your high side is well in check at 200 and pretty close to where it should be. Anything is a guess though without actually recovering and weighing the freon.
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