Signs of Motor Mount Failure on Your Mercedes

Mercedes-Benz is synonymous with luxury. A smooth, quiet, and refined ride sets a Benz apart from other vehicles. This refined driving experience often means you notice it right away when something isn’t right. 

You wouldn’t expect to feel much vibration from the engine of any car, but even the slightest bit of shaking on a Mercedes is a good indication of a problem. Pinpointing the exact cause of a vibration can be tricky without the proper knowledge and equipment. We are going to look at one of the more common causes of engine vibration in your Mercedes; failed motor mounts. 

What are Motor Mounts?

You may have never thought about how exactly the engine stays in your car. When you pop the hood, the engine seems to just be there. Newer vehicles are filled with plastic covers hiding virtually all of the engine, making it even harder to see what’s going on in there. 

Motors, and the transmissions connected to them, are extremely heavy. Many Mercedes vehicles have large V6, V8, or even V12 engines, adding significant weight to the car. Add that engines house mini explosions during combustion, and you are dealing with a big, heavy, vibrating piece of machinery.

Dealing with this weight and vibration is where motor mounts come in. Motor mounts bolt to the frame of your vehicle on one side, and the engine on the other. Their job is to support the engine and transmission and reduce vibrations felt by the driver and passengers. 

Silver Mercedes ML350

How do Motor Mounts Reduce Vibrations?

If the engine were bolted directly to the frame, the metal-on-metal contact point would transfer nearly all of the engine vibration to the rest of the vehicle, making for an unpleasant driving experience.

Motor mounts put a buffer between the engine and the rest of the car. Typically, they do this by incorporating a layer of rubber, polyurethane, or a fluid-filled chamber between the contact points. Some modern vehicles will employ electronic/active motor mounts as well. 

Mercedes-Benz utilizes rubber, hydraulic, and electronic motor mounts depending on the year and model of the vehicle. 

Mercedes ML350 Transmission Mount

What Causes Motor Mounts to Fail?

In almost all cases, motor mount failure is caused by wear and tear. Thousands of miles of driving, exposure to the elements, and the impacts of road debris, bumps, potholes, and curbs all contribute to motor mount failure.

Hydraulic Motor Mount Failure

When hydraulic mounts become damaged, they can leak fluid. Without hydraulic fluid, the motor mounts will not function as they should.

Rubber Motor Mount Failure 

Rubber Motor mounts can become cracked, dry-rotted, and worn out after years of use. Exposure to the elements will accelerate rubber motor mount failure. 

Active Motor Mount Failure

Active motor mounts (those that utilize electronics to control the mount) have an additional failure point. A short in the wiring can make the active feature stop working.  

Symptoms of Bad Motor Mounts in a Mercedes-Benz

While failing motor mounts can be pretty apparent to a passenger or technician, you may not notice anything wrong initially if you drive the car every day. Motor mounts tend to fail slowly, which means you will get used to the change in how your car drives. When the symptoms become severe, or someone who doesn’t usually ride in or drive the car notices something, you realize the mounts are not working as they should. Failed mounts can have the following symptoms:

  1. Increased Vibrations 

One of the most obvious signs of failed motor mounts is increased vibrations throughout the cabin. When the mounts fail, they cannot dampen the movement of the engine as well, meaning you will feel it more. You might also feel gear shifts more, as the mounts cannot reduce the movement of the transmission changing gears. 

  1. Jerky Start

The jarring torque and movement when you first start your engine will be felt throughout the car when your motor mounts are not working right. The jerking will only happen on startup and will settle into a steady vibration once the motor is running. 

  1. Clunking Noises

Severely failed mounts will allow the engine and transmission to move more. You might hear a banging or clunking noise when driving as the weight of the drivetrain moves. It’s important to get your Mercedes into a shop fast if you experience these symptoms to prevent further damage. 

Dirty Mercedes ML Motor Mount

Get your Mercedes Serviced at Orion Automotive!

If you suspect the motor mounts in your Mercedes are going bad, don’t delay! Bring your car to technicians with the knowledge and experience needed to service European vehicles like Mercedes-Benz. Give us a call or schedule an appointment online today and get the plush, smooth ride back that you expect from your Mercedes!

Book with our certified technicians today!


Book with our certified technicians today!