Why your AC blows cold air just for 5 minutes and then normal air comes through?

Answer 1

Usually, a gas leak might cause this problem. Have your car checked at a qualified professional.

Actually, if this cycle repeats whenever you operate the AC, then a leak will not be the problem. The expansion valve controls the release of high pressure liquid Freon and can fail in the mode of continuos release. It will cool like crazy, then "ice over" and circulate no Freon which leads to the normal (not cooled) air blowing. If you are comfortable checking under the hood (exercise caution around moving parts!!!), open it, then crank the car and start the AC. Looking in the engine compartment you will find a small aluminum cylinder perhaps 12" high and 4" in diameter usually located toward the front of the compartment. It will have a pipe leading into it at the top and one leading out (this is the receiver dryer and has the expansion valve attached) and will very quickly become cool to the touch. There is usually enough humidity in the air for ice to start forming around the expansion valve and the pipe going out of it. When the ice forms, you can be sure that the expansion valve is the problem. Now the bad news! While an expansion valve repair is not terribly expensive ($200 or less), it is often the impending failure of the compressor that causes the expansion valve to fail. The compressor starts throwing off small pieces of metal that contaminate the Freon flow and eventually accumulate in the expansion valve sufficiently to cause it to stick open. The repair will involve flushing the system to remove contaminates, replacing the compressor, expansion valve, and perhaps a few other components. Cost will be (depending on type of car) $500-$800 +++. You need to seek a qualified mechanic to verify the diagnose of the problem, and quote a repair. If it is within your budget, you will then have cold air continuously! FYI, be SURE to ask enough questions and be satisfied with the answers when choosing the repair shop.