How often do engine motor mounts need to be replaced?
The engine motor mounts on most vehicles are designed to isolate the engine’s normal movements and vibrations from the vehicle frame and body so the operator of the vehicle will not feel them. In some vehicles the motor mounts are made from solid rubber and others may be hollow rubber with a liquid filling. The solid rubber ones are used in most vehicle engines, while the liquid filled ones are used in vehicles that need additional isolation between the engine and body.
The motor mounts are subject to wear and tear depending on age and how the vehicle is driven. A vehicle with a manual transmission may break motor mounts more often depending on the abuse from the shifting of the transmission. The age of the mounts will vary depending on location. Just like old tires start to dry rot and crack, so do the motor mounts’ rubber. A solid motor mount may tear partly and still work fine, but a liquid filled motor mount will leak out the liquid and the motor mount will no longer dampen vibrations from the motor.
In general, motor mounts do not have a scheduled replacement but should last between 5 to 10 years before dry rot or breaking from age-related failure. Motor mounts can get broken from slamming the vehicle, gears over-revving, and letting out clutch or power braking the engine before takeoff. Motor mounts can break in vehicle accidents too. If the motor mounts break due to harsh transmission shifting, the transmission mounts may also get damaged. I have seen mounts break in a year or less due to outside failures. Engine oil or other fluid leaks may get on the mounts, deteriorate the rubber, and cause it premature failure.