Why Is My Car Shaking When Idle?

Why Is My Car Shaking When Idle? 


Have you ever experienced a rough idle or lots of shaking while you are stopped at a stop light or maybe you are slowing down, and it just starts to shake out of nowhere? There could be a variety of different reasons for this, it's not something you want to ignore as it may be a big underlying issue!

  We recently had a BMW X2 in the shop that was experiencing this symptom. Upon doing a full diagnosis to the vehicle, our technician found that this was coming from the Motor Mounts. After asking my Service Manager about this issue, he stated that Motor Mounts can have many names, and can be different depending on make and model of vehicle. For instance, trucks usually have Engine Mounts that are metal and rubber, whereas other vehicles like this BMW X2 have mounts that have rubber with liquid inside of them, also known as hydraulic fluid. For this vehicle, Chris our ASE Certified Master Import & European Technician, had to replace one Motor Mount and one Transmission Mount. 



  You may notice both parts end in "mounts", that is precisely their purpose, to keep the Engine "mounted" in place. Keeping the engine in place also requires that it is in place at an equal balance inside the vehicle. If you open the hood of your car and notice that the engine is drooping to one side or disproportional, then that is a for sure sign that you need new engine mounts. But our issue stems from pure vibration to the steering wheel. If you happen to notice this shaking and don't take care of it you are putting tremendous stress/damage on the Engine. If it gets off balance, you can expect it to shake from side to side, or bounce. 

  There are several different reasons for the motor mounts to go bad, but here are a few typical causes:

  • Age or Stress on the vehicle: Rubber doesn't last forever. In fact, when you stretch a rubber band several times, eventually you will notice small little cracks in the rubber. The motor mounts are holding in liquid, so over time you may notice small leaks occurring, and that is just from the normal wear and tear.
  • Accidents or any kind of Impact to the vehicle: Any kind of impact can have negative effects on the vehicle. The entire vehicle can become misaligned or shifted from its original position. A common occurrence with motor mounts cracking is because of fender benders. Make sure if you are purchasing a used vehicle, that you are getting the mounts checked out before purchase. We offer pre-purchase inspections at our shop, so we can make sure that any vehicle you are interested in purchasing gets our stamp of approval. 
  • Hydraulic fluid/Oil leaks: This can lead to the break down or disintegration of the rubber on the mounts. Make sure you have a Master mechanic like Chris, diagnose that there are no leaks coming from anywhere during inspection. 
  • Defective Mounts: Always be sure to look out and see if your vehicles manufacturer has put out any recalls for this specific part. 
  • Bad installation: Make sure you are taking your vehicle's to a reputable Auto Repair facility like ours to ensure that proper equipment is being used to install these mounts. Some vehicle's have mounts that are more complicated to replace, if done improperly, you can expect oil leaks, or total break down.  


 Signs of some hydraulic fluid leaking

  At the first signs of Motor mount failure, you may not notice a drastic change, but over time the vibration can get worse. As mentioned above, please make sure you are bringing your vehicle to a reputable shop with all the right equipment to fix this issue. Our team here at American Import Auto, Inc. has all the new and updated equipment to help diagnose and repair any issues for any and all vehicle makes and models! 



Motor Mounts
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