AC unit help needed.

silverfox20silverfox20 Member Posts: 1
edited July 2015 in Pontiac
I own a Pontiac Montana sv6. Past few weeks rad fan has been on constant. Gas mileage has dropped 40% or more. Last night I pulled both fuses for the ac and now rad fan is not sounding like a plane taking over anymore and gas mileage has returned to normal. Any suggestions on what ac problem could be causing the fan and gas issue?


  • 93tracker5spd93tracker5spd North East Ohio USAMember Posts: 194
    Without seeing the vehicle I can't be specific, but it is obvious that your AC compressor is not disengaging as it should. This causes your engine to run hotter and the cooling fan to come on or stay on more than normal, it also puts more labour drag on the engine, hence the reduced fuel mileage. This could be caused by one of three things, the compressor clutch malfunctioning, an electrical problem causing the compressor clutch to stay engaged all the time, or simply that the system is low on refrigerant and can't keep up with the demand. Either way it will require diagnoses by a qualified mechanic, or someone with experience and the right testing tools. Good luck, and post back so we will know what the problem really was please. A great day to you!
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