What Causes Motor Mounts to Go Bad?

Motor mounts deteriorate over time due to normal wear and tear, leading to excessive engine vibration and noise. The main causes of motor mount failure are high mileage, engine vibration, aggressive driving, rough roads, and engine modifications.

Symptoms include vibration in the steering wheel and cabin, clunking noises when accelerating, and engine oil leaks. It is unsafe to drive with damaged mounts, and replacement costs $250-$650 per mount on average.

This article discusses the common causes of motor mount failure, symptoms of bad mounts, whether it’s ok to drive with damaged mounts, preventative maintenance, repair costs, and answers what bad mounts sound like and how far you can drive with a failed mount.

What Causes Motor Mounts to Go Bad?

Motor mounts are rubber parts that connect the engine and transmission to the chassis of your vehicle. They are designed to dampen engine vibrations and noises while allowing the engine to move as needed. Over time, motor mounts can deteriorate and fail, leading to serious drivability issues. Here’s a closer look at what causes motor mounts to go bad.

Common Causes of Motor Mount Failure

• Age and Mileage: Motor mounts are made of rubber and other materials that naturally break down over time. Most motor mounts are designed to last 50,000-100,000 miles. High mileage vehicles are more prone to motor mount problems.
• Excessive Engine Vibration: Constant vibration from a rough running engine can cause motor mounts to crack and separate over time. This is common on older engines with worn internal parts.
• Hard Driving Habits: Aggressive driving with sudden acceleration and hard braking puts extra strain on motor mounts. This can lead to premature cracking and failure.
• Driving Over Rough Roads: Consistently driving over potholes, speed bumps and rough terrain taxes motor mounts. The impact and bouncing can damage rubber mounts.
• Heavy Engine Modifications: Altering the engine for more power increases vibration and torque loads. Upgraded turbochargers, superchargers, and performance mods shorten the life of stock motor mounts.

Symptoms of Bad Motor Mounts

• Excessive Vibration: When rubber separates from the metal mounting point, it allows more engine movement and vibration to transfer to the chassis. This causes shaking in the steering wheel, seat, and floorboards.
• Clunking or Banging Noises: Damaged mounts can allow the engine to violently rock and collide with the engine bay when starting from a stop. This creates loud clunks and bangs.
• Oil Leaks: Cracked rubber can allow engine oil to leak through the mount. Check for oil collecting on the mount or dripping underneath the engine.

Is it OK to Drive With Bad Motor Mounts?

No, You should not drive with broken or damaged motor mounts. Bad motor mounts prevent proper engine movement and operation. Continued driving could lead to catastrophic engine damage or failure. Have bad mounts replaced by a certified mechanic as soon as possible.

How to Prevent Motor Mount Failure

• Regular Maintenance: Follow your vehicle’s maintenance schedule for oil changes, tune-ups, and inspection. This helps maintain engine performance and prevents excess vibration.
• Avoid Hard Acceleration/Braking: Sudden starts and stops strain powertrain components. Accelerate and brake gradually for smoother driving.
• Drive Smoothly Over Rough Roads: Slow down on uneven roads and avoid potholes to reduce impact on mounts.
• Avoid Overloading Vehicle: Carrying heavy loads puts more stress on motor mounts. Do not exceed vehicle payload capacity.
• Get Regular Oil Changes and Tune-Ups: Well-maintained engines run smoother and cause less vibration. Follow the owner’s manual service intervals.

How Much Does it Cost to Repair Motor Mounts?

Motor mount replacement costs $250-$650 per mount on average. The labor time is 1-3 hours. Luxury and high-performance vehicles are more expensive. Replacing all engine and transmission mounts at once reduces labor time for a lower total cost.

What does a bad motor mount sound like?

A bad motor mount may produce a loud clunking, banging, or knocking sound when starting from a stop as the engine rocks violently against the damaged rubber. A bad mount can also cause the engine to make a loud rattling noise as vibrations are transferred through the bad rubber bushing.

How long can you drive with a bad motor mount?

It is not recommended to drive any considerable distance with a severely damaged motor mount. The excessive engine movement can lead to damaged powertrain components and oil leaks. However, driving 5-10 miles to a repair shop on surface streets is generally safe after a mount fails. Avoid extended driving and high speeds.

What are motor mounts?

Motor mounts are rubber-and-metal fasteners that secure the engine and transmission to the vehicle frame while insulating powertrain vibrations and noise. Most vehicles have three mounts – one on each side near the front, and a rear mount under the transmission. Motor mounts allow the engine to rock and move without rattling the chassis. They prevent engine torque from twisting the frame.