Mechanics

Engine Mount

AD
Step by step guide on how an automotive engine mount works, this information pertains to most vehicles.

Step 1 - Engine mounts are designed to isolate the vehicle from vibrations and harmonics created by the engine. Created using two metal plates vulcanized together with a sizable piece of rubber or a liquid filled bladder. The lower plate is bolted to the frame whereas the upper metal plate bolts to the engine allowing slight movement from the engine. These mounts are also used for the transmission, and perform the same operation. In a rear wheel drive vehicles there are usually two mounts, one on either side of the engine, with one mount used for the transmission. Front wheel drive applications may incorporate more mounts to help control engine torque. Front wheel drive vehicles sometimes incorporate a “dog bone” or torque mount to control the twisting of the engine.


Engine Mount

Step 2 - When an engine mount fails it can cause a heavy clunk when accelerating which indicates the engine moving around in the engine compartment. Other times the engine vibration may become more pronounced due to the mount collapsing, this will transfer the vibrations of the engine to the frame. In front wheel drive vehicles, a broken mount can cause the axle to fail or pop out of the transmission, causing the vehicle to stop moving. Oil contamination, hard shifting (manual transmission), excessive high idle, or the combination of age and engine compartment heat can cause engine mount failure. To inspect engine mounts use a flashlight and check for deterioration or tears from the weight of the engine.

AD

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


COMMENTS TO THIS ARTICLE


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.



Article first published (Updated 2014-07-24)