Q: Aircond intermittently blows warm air and indicates engine overheat but engine seems to be normal

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I have a 2002 Lexus LS430. Two years ago I had my cooling coil replaced due to some leak. Recently, somedays the air-con blows warm air on cold start but turns cold after a few minutes or once driven. Otherdays air-con is A ok. It has been this way for several months now and recently the air-con blew warm air while driven with the temperature meter indicating engine overheat. Opened the hood but engine appears normally warm. What could be the problem and what should be replaced or repaired if necessary?

My car has 132195 miles.
My car has an automatic transmission.

It sounds like you may have a faulty AC Compressor or potentially a leak in the AC lines somewhere. Car air conditioners work on a simple principle of heat transfer, relying on the fact that heat will always transfer from a warmer to a cooler substance. The A/C uses a compressor to turn a refrigerant gas, usually Freon, into a liquid concentrating its heat. In this state, it passes through conductive pipes in a condenser to dissipate the accumulated heat. As the liquid leaves the condenser and returns to its natural gaseous state it becomes very cold. The A/C system pumps this cooled refrigerant through a series of very thin tubes while blowing warm air over them to cool it before it enters the cabin of the vehicle. The heat from the air is absorbed through the tubes by the Freon gas, which returns to the compressor to begin the cycle again. I would suggest having a professional from YourMechanic come to your location to take a look at your vehicle.

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