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Broken Engine Mounts, Your Dentists Best Friend

Broken Engine Mounts, Your Dentists Best FriendBroken Engine Mounts, Your Dentists Best FriendBroken Engine Mounts, Your Dentists Best Friend

The engine and transmission in your vehicle are attached to the chassis. When they operate, it creates flexing and twisting from torque or vibrations. There are mounts that hold and support these two units. Mounts for the Engine and transmission are most typically made of metal and rubber, or somtimes filled with a hydraulic fluid.

These mounts keep your teeth from vibrating out of your skull by separating the transmission and engine from the chassis so that there is no direct metal on metal contact between the engine, transmission and frame of the vehicle.

To improve passenger comfort, some vehicles have fluid-filled hydraulic mounts which absorb and dampen vibrations that would otherwise pass right through a conventional solid rubber mount. While comfort is something we all enjoy, fluid-filled mounts are more expensive than solid rubber mounts, and they can leak fluid and can still collapse after years of service.

Some import vehicles have electronically-controlled mounts that can alter the stiffness of the mount to cancel out harmonics at various engine speeds and load weights. These mounts can use a vacuum-actuator to change the stiffness of the mount, and some even generate their own counter shake to offset engine vibrations at various speeds.

Today, most front-wheel drive cars, SUVs, and minivans use transverse-mounted engines and transaxles. This means the engine is mounted perpendicular (sideways) to the centerline of the vehicle. This style of engine mounting usually requires either three or four mounts for the engine and transaxle to be properly secured to the frame.

On rear-wheel drive cars and trucks, there is usually a pair of engine mounts on each side of the engine to support the engine, and a single mount under the back of the transmission.

Upper engine mounts are sometimes used and are often called 'struts' or 'dog bones'. They prevent the engine from rocking back and forth as the vehicle accelerates and decelerates. Upper mounts usually have a rubber bushing with metal sleeves in each end. One end is attached to the engine and the other to the radiator cross member support.

Mounts deteriorate with age and mileage, so it's not unusual to find one or more broken or collapsed mounts in older or high-mileage vehicles. If one mount has failed, chances are the other mounts are near the end of their service life and should also be replaced.

Cracked, loose, leaking, or broken mounts may allow excessive engine and transaxle movement which in turn could cause damage and misalignment of important components. Faulty engine and transmission mounts are often a cause of excessive engine noise and vibration, and can also result in clunking and banging noises when placing the transmission into gear or accelerating. Continual stretching and pressure on engine and transmission mounts will eventually take a toll. Broken mounts can create engine and transmission "sag", which puts too much pressure on the axles, causing them to fail prematurely from the extra stress.

Due to the amount of vibration an engine generates as part of its operation, engine and transmission mounts are an essential component on any vehicle. When engine mounts fail, not only will the vibration and noise in the cabin be uncomfortable for the driver and passengers, additional strain will be placed on the engine that can damage other components.

Often, excessive vibration resulting from faulty engine and transmission mounts is more noticeable at idle with the transmission engaged. If you suspect your engine and transmission mounts may need attention, have the vehicle inspected by a One Stop Automotive technician right away.