A/C blows warm air.

I had just recarged my ac at a shop, and now its two weeks later and it went out I looked for leaks could not find any, anything I should look for.

Hello,

I own a 2001 Nissan Sentra and I have just recently had problems with my AC. It works when I drive (Not as cold as it was before it started acting up but cold enough)but when I idol or stop at a stop sign it blows only hot air. What is wrong with it and how can I fix it? Will it cost me an arm and a leg to get it fixed? I need help alot because where I live it is dry season and hotter than a desert in the summer.

Thank you,
Denise P. Guam

This has me puzzled. My heater works great as long as I am driving a distance. However, if I am in town to run errands it starts blowing cold. If I want to warm my car before leaving for work it only blows cold. The rmps have to be high in order for it to blow warm. It worked great last winter and it does this winter as long as I"m not in town. Example. I left work to come home which is appx 12 mles. I have to run to the store and within 3 to 4 minutesof driving in town it only blows cold. As soon as I leave town where I"m driving 55mph it is blowing warm as it should. Any suggestions?
My car is a 2000 Nissian Sentra 1.8 engine.

Okay thanks but. I just replaced my thermostat and the heater core has been flushed. The door whatever you want to call it is controlled by a cable and it was also checked. Any other suggestions?

All of a sudden my a/c starting blowing nothing but hot air and there seems to be no obvious issues. The compressor was changed at the end of last summer, so it is brand new. Please help with any suggestions as to what may cause this. Thanks.

I have a 2000 Sentra Se 2.0, about 145K. AC worked, but took a while to get cold, and didn't get as cold as it used to. I figured it just needed a recharge.
I took it to a generic tire and auto place, and was told the low pressure line was leaking. Since the place dealt mainly with tires and suspension, I decided to take it to a place I trust.
This place didn't find the leak in the low pressure line, but when they went to recharge the AC system, they found a broken seal in the compressor and all the fluid leaked out. They told me that the compressor needed to be replaced. I normally trust this place, but my repair estimate just jumped from 250 to almost 1000. Can you tell from this info which place gave the right diagnosis?
Also, will a remanufactured compressor work as well as a new? I plan to keep the car as long as possible, so is it worth an extra $300 to buy new?
Thanks

When I turn my ac on it can cool for some times then it's stop and blowing warm air also when the ac is making that change either cooling or stop cooling the engine feels like it holds then goes or lose power I alredy change the compressor can you help me please.

Air Conditioning problem
1992 Nissan Sentra 4 cyl Front Wheel Drive Manual

The AC seems to work randomly. When it works, it blows cold. Worked every day for the last two weeks, then yesterday no. When turned on, the compressor engages, slight load on engine, and either blows very cold air, or slightly cool air. I had the system pressured checked, no leaks. Mechanic added more freon, but only took small amount of one can. What else in the AC system can control whether it blows cold or not? A relay? A breaker of some sort?

The mechanic seemed more interested in selling me on the conversion idea, especially by the time that I spent the money replacing the old freon.
I don't know if this has any bering on the subject, but when I start the car and turn on the AC, it will either work or not work until the next time I start the car. It never stops working in the middle while I'm driving.

Do you know how many cans of freon that system would take? Whether I do the conversion, or replace the expansion valve, it looks like big bucks either way.
When it comes to replacing the expansion valve, are we talking complicated enough to diffinently let a mechanic handle it? I guess there is no easy, or most of all inexpensive way out of it.