This is driving me crazy and I need to ask before the summer is over. I have a 2017 QX60 and the AC has been acting strange for about a month. When I am driving on the road, the air is nice and cold. But the moment I stop at a traffic signal or sit in the parking lot with the engine on, it turns warm in a minute or two. Then when I start moving again, it slowly gets cold. My wife says it is just the weather, but I have lived here many years and this car never did this before. Last week I also noticed a weak smell from the vents, kind of damp and sour, like old socks. The kids in the back complain about it all the time. Yesterday I looked at the front of the car and saw some oily dirty marks on one of the pipes near the engine, but I am not sure if that is related. A friend of mine said it is the gas that is low and I just need a refill. Another friend said the compressor is dying and that costs a lot. A third one said it could be only the cooling fan not working properly. So now I have three answers and no idea which is true. I read a page from a workshop in Mussafah that explained how the AC system works, like the compressor, the condenser, the gas and the cabin filter, and how a leak or a dirty part can make the cold air come and go. It was easy to follow, and it made me understand that a simple refill may not solve it if there is a leak somewhere. I also typed Premium AC repair for Infiniti in Khalifa City on my phone one night because I live near there and I do not want to drive far in this heat. But I want to learn before I call anyone. So my questions are these. How do you find out if the gas is low or if there is a leak, is there a simple test they do? Is it normal for the cold air to go warm when the car is not moving, or does that point to the fan? What about the smell, can a new cabin filter fix it, or do they have to clean the inside of the system? I heard some places just add gas every year and never fix the real problem. Is that true, and how can I avoid it? How long does an AC job take, and what is a fair price for a compressor if it must be changed? If you had the same problem, please tell me what the cause was in your car. Thanks a lot, I will check the replies tonight.