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Q: Car loses some engine power when the blower is turned on.

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While driving down the interstate I had a loud belt squeal. When that happened I turned off the radio and my heat. When I turned the fan off I had full acceleration. I turned the fan to low and it had a light sqeek and some off of acceleration. At highway speed I was about 3000 rpms.

My car has 112114 miles.
My car has a manual transmission.

A minor loss of power when the fan is engaged is probably due to the air conditioning compressor. When the air conditioning, or the heater, is switched on, it activates the compressor. The light squeal is most likely coming from the compressor clutch being engaged when the system is activated, and the actual squeal could be coming from either the belt, or the clutch itself. As with all engine driven compressors, they will rob a small amount of power from the engine. This is why you will typically see a decline in fuel economy when either the heater, or air conditioner, is being used. If the noise, or power loss, seem excessive, you may want to have a certified mechanic, like those available at YourMechanic.com, take a look at the compressor and clutch assembly to be sure there is not an issue that is beginning to show itself.

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