The primary function of an engine mount is to support the engine and isolate engine vibrations from the vehicle chassis. One part of the engine mount is bolted to the car body or frame. Another part holds the engine. An engine is a source of vibration, as it has many moving and rotating parts. The job of an engine mount is not only to hold the engine in place, but to reduce the engine vibration felt inside the car.
Engine mounts are made with a rubber material so that there is no direct metal-to-metal contact between the engine and the car body. Main symptom of a failing engine mount is increase in the engine vibration and noise.