Car vibrates when standing with a/c on

2012 HYUNDAI I30
1.6L • AUTOMATIC
Avatar
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
Advertisement
Avatar
JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
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
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.