Hi everyone, thanks for the replies!
(1) Keep the car, no change.
This was always an option, considering I wasn't too happy to throw a wedding out the door for a car.
...Otherwise, I'd regard the AC issue as a statistical anomaly and keep going until something does happen or you can afford to pay cash for an upgrade. If you have a solid reason to distrust the car - more than you've stated - make an even trade, your $4000 car for another.
From what I have heard, this year is the better of the lot especially with a mileage of 65k.
Thanks for the suggestions. I will probably keep saving up for a car until the next issue happens on the car.