Originally Posted by
7milesout
5° might be difficult to discern on that gauge. I done got one. It's difficult to read it while driving. It's daggone small. Especially for dinosaurs.
Dirk - The quickest best way to check for a leak is to evacuate the refrigerant, pull a deep vacuum on the system, turn off the vacuum pump and let it sit in vacuum state for ~30 minutes. Drink beer or smoke some of that wacky tobacky you got, then go look at the vacuum gauge. If it has lost vacuum there is a leak.
NOPE. The people you had check / fill your system, no way they evacuated for the cost they charged you.
The vacuum does 2 things. Makes a leak apparent, and evaporates water (vapor) out of the system (thusly improving cooling performance). Once that's done, refrigerant can be added, brought up to the official capacity. But if it has a leak, it's gonna leak out. If the leak is miniscule, it might be worth doing, yearly or every 2 years. If the leak is large, it is better to find and fix the leak. Leak repair can be expensive. It can be inexpensive too.
My impression by your description is that you have a leak but it is small to miniscule. Losing cooling performance at idle is common. The compressor (I believe) is "rated" for some level of performance, but it will be at some rpm above idle. Probably in the 2,500 to 3,500 rpm zone. I don't know. That's an HVAC engineer's thang.
If I were you, for now, I'd monitor the situation. My Blueberry, I can feel the A/C not do as well at idle. But it's system is pretty small. My Lexus and Ram have 4 or 5 times the capacity of the Mirage. The Lexus has a whole nother evaporator for the rear seat occupants. The Lexus will put the women on HIGH beams in short order. The Ram, I don't know why it has so much capacity. Bigger is better I guess.
P.S. You may notice a blue streak passing your neighborhood, ohhhhh about 7 pm. I'm heading up to Cartersville to meet my sister and B-I-L to have dinner with them. I'm also gonna use the Northwest Corridor because I'm so high fallootin'. I don't know where your homestead is in relation to the I-285 / I-75 interchange & the Northwest Corridor.