How to Check for a Broken Motor Mount in a Mercedes


1. Open your Mercedes-Benz hood and use the hood rod to secure it in an upright position. Some Mercedes hoods do not have a hood rod and the hood will stay up on its own.
2. Locate your engine's motor mounts. Use your owner's manual to help you locate the exact positioning of your motor mounts. The number of motor mounts may vary depending on your Mercedes model.
3. Visually examine the motor mounts. Observe if there are cracks, separations in the rubber from the metal, missing bolts, broken brackets, fluid leaking or warped or compressed rubber. Any of the visual signs of deterioration or damage will indicate that the motor mount needs to be changed.
4. Use a flat-head screwdriver to press down on the rubber part of the motor mount. If the rubber does not bounce right back into place and instead stays compressed, then you need to replace your motor mounts.
5. Start your Mercedes engine. Place your 'Emergency Brake' into the 'ON' position. Keep your foot tightly on the brake pedal while switching your Mercedes into the 'Drive' gear. With your foot pressed down on the brake pedal, slowly press down on the gas pedal to rev your engine. Monitor your rpm and do not allow the engine to enter the 'Red Zone' on your rpm dial, as this can damage your vehicle. If the engine revs and you do not feel a vibration by your feet, your engine mounts should be in good condition. Revving the engine will cause the engine to shake when the motor mounts are not securely holding the engine into place. The shaking will cause a noticeable vibration and shaking inside of the vehicle, which will let you know it is time to replace your motor mounts.
6. Drive your Mercedes around in an empty parking lot or on a street with little traffic. Press your foot on the gas pedal to accelerate. While accelerating, notice if you feel any vibrations. Abruptly press your foot on the brake. If the vehicle shakes from side to side while slowing down, then you need to replace your motor mounts.