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Q: Ac not cooling properly.

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Had a new ac compressor and drier installed last week. The old compressor would make a lot of noise when turning on the ac and it was not cooling much at all. After having it installed by a local mechanic along with the a new drier I noticed the ac only cools when turning on the recirculation button on. I took an ac thermometer to check the temperature on the center vent and it would go as low as 48F with recirculation on. With the recirculation button off the lowest temperature is 64F. And the air feels dry and warm for 64F. It takes 20 minutes for the ac to cool with the recirculation button on to 48F. I also noticed the gas mileage dropped from 16.7 to 16.2 mpg after having the compressor installed. The mechanic who installed the compressor and drier said everything is fine. What could be the issue for not cooling without the recirculation and for it to take a long time to cool well with recirculation?

A: Hello. Thanks for writing in about your 200...

Hello. Thanks for writing in about your 2005 Toyota 4Runner. You could try purchasing another thermometer to check the level, but the system’s instruments don’t typically give false readings. The conditions outside can affect the operation of the system as well. The recirculation option takes air from inside the vehicle and pushes it through the air conditioning system a second time, and this process will generally provide a bit of extra cooling.

One option can be to have the system evacuated of refrigerant and held under a vacuum for a couple of hours to boil out any moisture, as water will begin to boil once you remove atmospheric pressure.

After this time, the system can be refilled and new oil added. If your vehicle has a cabin air filter, try checking to see if it’s dirty and blocking air flow to the AC system in-cabin fan. If you want to have a professional diagnose the AC system before making any adjustments or repairs, a certified technician from YourMechanic can come to your home or office to perform this service.

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