Car vibrates when standing with a/c on

2012 HYUNDAI I30
1.6L • AUTOMATIC
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JOHNY84
  • MEMBER
  • 1 POST
Dear all,

I have 2012 Hyundai with 1.6 petrol engine. To explain my problem:

When i'm driving with a/c on, every time I stop, the car starts vibrating (revs are normal). If i hit the gas, vibration stops. If put it in neutral, the vibration subsides. If I turn the a/c off, almost no vibration at all.

Anyone ?

Thanks!
Sep 10, 2014 at 3:25 AM
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JACOBANDNICKOLAS
  • CERTIFIED EXPERT
  • 110,175 POSTS
The AC puts an additional load on the engine. As a result, a sensor called the idle air control valve needs to increase the engine RPM's to compensate for the added load. If it doesn't function properly, it could allow the RPM's to slightly drop. Thus, you feel a vibration. You mentioned that the RPM's are okay. Are you sure they are not dropping with the AC on? Do a little test. Start the engine, let it idle with the AC off. While watching the tach, turn the AC on. Is there any change in RPM's? If there isn't, it could be a few other things such as a bad motor mount allowing vibration to be felt, a compressor that is going bad...
Sep 10, 2014 at 5:06 AM