Its a 2000 Jimmy and i recently had to put freon in it and its back to blowing as cold as when i first bought it back in feb but its certainly not enough for the florida summer. it has 200k plus on it and im not sure how much a/c work is original. i notice that when im driving and start accelerating quickly i.e. like on the on ramp to get on the interstate the cold just goes away but the air still blows the same. Also, when i have the a/c on it gets TERRIBLE gas mileage and feels very sluggish. i dont know where to start so any help would be much appreciated..

 

Was the system evacuated before adding refrigerant? Was the correct amount added? We need to know what high and low side pressures are, along with ambient temp, when the engine is at 1500 rpm, AC set to MAX, doors and windows closed. The pressures we need are: High side the instant that the compressor shuts off, low side when the compressor turns on and off. Compressor "on" time, "off" time, and total cycle time.

 

ok the only thing i did was add freon and i followed the directions on the bottle as far as how to add and when to stop as far as pressure readings ill have to take it to a place and have them do those tests. I did however turn it on this morning on the way to work and noticed the compressor clicking on and off again and it was barely cold so im thinking i have a leak somewhere in the system

 

It's impossible to tell how much refrigerant is in the system by monitoring pressures. Pressures and cycle times are used for diagnosis, that's all. On this system, there is no 'dipstick": The only way to know how much refrigerant is in the system, is to drain it, evacuate it, and charge it with the proper amount. As little as 2 ounces off will cause problems. If it's undercharged it will not cool properly. If it's overcharged, it will not cool properly and it can cause catastrophic damage to the system, and the person working on it. Without the proper tools and training, it's best to have a pro look at it. The DIY "add-a-can" isn't called "death kit" for nothin' ya know

 

gotcha thanks for the head up ill have it checked out ASAP

 

When you have them do the system performance test, it wouldn't hurt to have them do a refrigerant purity test, as well. It should be something they do as part of the system performance test, but some places will cut corners.