Your engine mounts keep various components under your hood securely in place on the chassis, dampening vibration and roughness, and ensuring the engine and transmission stay properly aligned with the rest of the drivetrain. Cut down on the excessive vibration and noise and replace the engine mounts in your vehicle in an afternoon with the right parts from makers like Anchor, ACDelco, Motorcraft and Beck/Arnley.
The engine mounts and transmission mounts are what keep your engine from thrashing around inside the frame and engine compartment. They also isolate your car from the vibrations and roughness of the engine. Motor mounts are typically a rubber piece bracketed by two metal plates (sometimes with an oil-filled or hydraulic core), connecting the engine to frame members at two or three strategic spots.
Failing motor mounts that allow the engine to move around too much can put stress on wiring harnesses and other parts. In extreme cases, a failed motor mount can even allow the engine to shift forward so much that the fan touches the radiator. Signs of motor mount failure (more common on front-wheel-drive vehicles) include a clunk while accelerating or decelerating and vibration or roughness from the front end. If you're in doubt, just put the vehicle in gear with the hood up and press the gas pedal while holding the brake. Have a friend watch and see if the engine tries to move around excessively while you do this.