Humming noise while AC fans are on

[GazV8]

Greetings,

I have a 2018 GT with 97,000kM on it. Lately, while idle and AC on there is a "humming" sound that barely auidable from the front side that gets louder however, with each "hum wave" there is a slight shake felt in the car steering wheel, seats and doors. Waves are random and mostly consistent. Whenever I turn off the AC the humming continuos as long as the fans are still running. After few minute of switching off the AC, the fans stop and the humming goes away. Any thoughts ?

Thanks

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[Emilbadal]

It’s difficult to say what might be…but since you mentioned that there’s a shake that’s being felt each time compressor kicks in… you need to get your AC checked out by a decent and trustworthy mechanic….if your compressor is starting to go bad it’s best to be pro-active about it…you don’t want your compressor to torpedo other parts of your AC system. I don’t mean to scare you, it may be something as easy as recharging your refrigerant…the bottom line is, get it checked out as soon as you can.

 

[Cobra Jet]

^^^ As was stated above, take it to a Ford Service Center or a reputable mechanic. If using the A/C or defroster, both events will kick on the electric fans and the car should not “hum” or vibrate violently as you are describing.

if you are feeling a violent shake in the doors from the A/C being on, it’s possible there is a more serious issue occurring. Have you parked the car and let it idle safely in neutral - popped the hood, then turn on the A/C to see if you can see anything wobbling at the front of the engine (or motor mount area)?

 

[GazV8]

@Emilbadal @Cobra Jet

I think it is related to motor mounts. When it in Park or Neutral it vibrates depend on the outside environemnt. If on even road it does not vibrate, uneven or bad road vibrate. If I put it on drive and hold the breaks there is no vibration what so ever, super smooth. Based on my limited mech experiance it has something to do with motor mounts, any ideas ?

 

[Emilbadal]

First do what Cobra Jet suggested. Observe the engine bay when the car is in park and AC is on and see if you can see where the noise or vibration is happening. Make sure you take all the safety precautions of inspecting the engine bay while engine is running. (Eye protection, No ties, or loose cloths or long hair etc.)

I doubt it's a motor mount issue but it might be. Usually, bad motor mounts, cause more vibration in gear and with brakes applied(engaged). Bad motor mounts give rumbling sense of vibration while moving and it's more constant. The test is relatively easy for motor mounts though. You can search for it on Youtube.

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