No matter how quiet and smooth a car appears to drive, it still relies on an internal combustion engine to produce tons of raw explosive power every minute. That engine sits in a compartment surrounded by other components that help your vehicle to run safely.

With such a powerful furnace at the heart of your vehicle, how is it that you don’t feel a thing? The answer: your car is equipped with multiple motor mounts that absorb the vibrations from your engine. Different vehicles may have different numbers of motor mounts depending on their model and year of manufacturing.

Your car’s internal combustion engine weighs several hundred pounds at minimum, as well as rotates, vibrates, and rattles around when you drive it. Left to its own devices, it would shake to pieces or ruin the other components surrounding it.

Motor mounts are installed in all vehicles to stabilize the engine and prevent the natural vibrations from the internal combustion process from damaging nearby components and being noticed by the driver. Motor mounts can also be called engine mounts.

Each motor mount is connected in two places: to the car body and to the engine itself. Motor mounts are typically made of rubber or similar materials to prevent metal-to-metal contact between the car body and the engine itself.

Depending on your car’s make and model, it may have motor mounts of a few different types:

Your vehicle’s owner’s manual may tell you what motor mounts your vehicle is equipped with, which may be helpful for future maintenance. 

Typical vehicles have between three and four motor mounts depending on their size and the stability of their engine. Certain cars may have four mounts due to how the engine is positioned relative to its other car body components and vice versa. Again, your car’s manual will likely contain these details.

Upon inspection, you might notice a fourth or fifth mount somewhere around your main engine’s apparatus. It’s probably the transmission mount, a separate mount designed to keep the transmission in place even as it moves and shifts with changing gears and torque levels.

Because motor mounts are exposed to stress over time, they can occasionally fail and wear down. As motor mounts are exposed to intense heat, vibration, oxygen, and ozone, their materials may eventually degrade.

In rubber’s case, for example, the rubber comprising the mounts will eventually stiffen. Hardened rubber is less capable of absorbing vibration and will become more brittle over time. When your mounts don't work correctly, your engine’s vibrations could transmit to your car's body. You might even feel them every time you start up the engine and take your car for a drive.

When left unchecked, motor mounts can eventually crack or break entirely. As you might expect, broken motor mounts can lead to a whole host of other engine problems, including:

You never want your motor mounts to fail entirely. Your car repair bills could quickly skyrocket if you leave damaged motor mounts to fester.

Fortunately, you can replace motor mounts at most auto repair shops that perform service for your vehicle’s model.

Certain engine mounts are “non-load bearing.” In this case, mechanics can quickly unbolt the motor mount and bolt in a new mount in as little as an hour or so. In other cases, the damaged mounts might be “load-bearing” (meaning they support a significant proportion of the engine’s weight in addition to dampening vibrations). These mounts are more difficult to replace, and mechanics may need to use engine support bars or jacks when replacing them.

Further complicating things is the fact that many modern vehicles have relatively claustrophobic or cramped engine compartments. If the compartment is too cramped, it may be difficult for mechanics to get to damaged motor mounts without taking apart other pieces of your vehicle or moving other components, extending the repair process.

All of these factors can lead to a pricey repair bill the longer you leave your motor mounts to rattle around when you hear them shifting. Bottom line: get your motor mounts looked at ASAP if you think that one or more of them are loose, cracked, or about to break.

Depending on your vehicle and the materials used to make the motor mounts, they may last for decades, if not the car’s entire lifespan. But it’s a good idea to get your motor mounts checked every seven years or so. 

Checking your motor mounts will help you stay ahead of any maintenance problems before they become significant issues.

Your car’s transmission mount should last for significantly longer than any motor mounts. You should not need to replace it before the car is either scrapped or totally rebuilt.

Typical motor mount replacements will cost anywhere between $100 and $400 depending on:

Still, it’s essential to get your motor mounts replaced when you notice a problem before your vibrating engine damages other parts of your vehicle.

To recap, most cars have between three and four motor mounts, which serve the important and unique purpose of absorbing vibrations from the engine’s internal combustion process. Some motor mounts may also help to support the weight of your car’s engine.

Motor mounts are typically made of rubber, though some may be filled with shock-absorbing fluid or even tiny vacuum chambers. Regardless, motor mounts can and do wear down over time, and you should pay attention to signs of degradation so you can get them replaced or repaired soon after the first signs of trouble.

Real insights from real owners

© 2022 J.D.Power. All rights reserved.

© 2019 J.D.Power. All rights reserved.