A/C knocks when it is on and idles rough at stops

AHELTON

MEMBER
2010 DODGE CALIBER
140,000 MILES

On interstate it is cool an very little noise. I checked Freon with AC Pro Gauge and it is in the red. I do not remember any one messing with A/C system since I had the car. I bought it used and have it 7 years and no issues with A/C. Why is it saying overcharged? Can I release a little Freon to see if that will help the noise and run better? It started about a year ago. I travel from Florida to Michigan a few times a year and about to head back next week. It seems to be worse in the hotter weather. Any help is appreciated. Thank you!

1 Reply

JIS001

MECHANIC
3,411 POSTS

Hello and welcome to 2CarPros. I would not recommend you just release Freon onto the atmosphere. I would recommend you take it in to a shop and have the system evacuated to see how much Freon is in there and recharge it with the proper amount. And with the rough running I would suspect a faulty condenser fan.

Also if the low side reads high, what does the high side read? If you can get those readings we can look into a possible restriction, faulty fans, faulty expansion valve, or faulty compressor just to start! Here is a tutorial on how the A/C works:

https://www.2carpros.com/articles/how-a-car-air-conditioner-works