Engine mounts are rubber or hydraulic cushions that connect the engine to the frame of a vehicle. They absorb vibrations from the engine to prevent them from transferring to the rest of the chassis. Over time, engine mounts can wear out and fail. But how often does this actually happen?
Engine mounts breaking is a common issue for aging vehicles. Industry statistics indicate that most engine mounts need replacement every 50,000 to 100,000 miles on average. The passenger side mount tends to fail first. Driving conditions, vehicle maintenance, and mount type impact lifespan. Replacing broken mounts costs $350-$900 including parts and labor.
This article explores the failure rates, causes, symptoms, prevention, and repair costs associated with broken motor mounts in detail. Main topics covered include failure statistics, lifespan factors, signs of bad mounts, reasons mounts break, prevention tips, and full replacement costs.
Statistics on Engine Mount Failure Rates
Industry experts estimate that most engine mounts will need replacing every 50,000 to 100,000 miles on average. However, this can vary substantially based on driving conditions and maintenance habits. Luxury vehicles and sports cars tend to require mount replacements more frequently, while mounts on basic economy cars and trucks may last over 100,000 miles.
Surveys of professional mechanics indicate that 5-10% of vehicles brought into repair shops need new engine mounts. For vehicles over 100,000 miles, this rate jumps to 15-25%.
Factors That Can Affect the Lifespan of Engine Mounts
Several key factors impact how long engine mounts last:
- Age of the Vehicle: Engine mounts deteriorate over time. Older vehicles are much more prone to mount failure than newer ones. Rubber compounds harden and crack after 5-10 years.
- Mileage: The more miles driven, the more stress and wear on engine mounts. High-mileage vehicles almost always need mounts replaced.
- Driving Conditions: Stop-and-go driving, potholes, curbs, and other rough conditions accelerate mount wear. Towing heavy loads also strains mounts.
- Vehicle Type: Trucks and performance cars produce more engine torque and vibration, demanding more from mounts.
Signs of Broken Engine Mounts
Listen and feel for these symptoms of broken motor mounts:
- Excessive Engine Vibration: Worn mounts allow the engine to shake more freely. Vibrations increase when idling in gear.
- Clunking Noises: Bad mounts can let the engine rock back and forth on acceleration, producing a clunking or banging noise.
- Uneven Idle: Engine rpm may surge up and down at idle with broken mounts.
- Difficult Steering: Excessive engine movement can overload the steering system.
- Fluid Leaks: Damaged mounts allow the engine to torque and twist more, potentially rupturing coolant hoses, vacuum lines, or oil pans.
Causes of Engine Mount Failure
Why do engine mounts wear out and break?
- Age and Mileage: The rubber and hydraulic fluid in mounts degrade over time and use. After 50,000-100,000 miles, failure risk rapidly increases.
- Oil and Coolant Leaks: Chemical contamination from leaks accelerates degradation of rubber.
- Excessive Vibration: Overloading mounts with torque and shaking damages the rubber. Performance engines generate more vibration.
- Heavy Loads: Towing heavy trailers or hauling heavy payloads strains mounts beyond their capacity.
- Impact Damage: Hitting potholes or curbs at speed can crack or tear motor mounts.
Read our complete guide on “What Causes Motor Mounts to Go Bad?” for more depth.
How to Prevent Engine Mounts From Breaking
You can prolong the life of your engine mounts:
- Perform regular maintenance and have mounts inspected after 50,000 miles.
- Avoid potholes and curbs whenever possible. Take speed bumps at an angle.
- Don’t haul or tow heavy loads daily. Go easy on the gas from a stop.
- Fix any leaks immediately and have damaged mounts replaced.
Cost of Replacing Engine Mounts
- Parts cost $50-$150 per mount, so $200-$600 for the full set.
- Labor runs $150-$300 for mount replacement.
- Total repair bills range from $350 for basic vehicles to $900 or more for luxury cars.
Are broken motor mounts expensive to fix?
Yes, Replacing broken engine mounts can cost $350-$900 in total between parts and labor costs, so it is an expensive repair. Luxury and performance vehicles tend to be the most costly.
What engine mount goes bad first?
The passenger side motor mount typically fails first, as it handles more engine torque and vibration stress than the driver side mount.
How long does it take new motor mounts to break in?
It usually takes 100-200 miles of driving for new engine mounts to fully settle in and “break in.” Vibrations will decrease after this period as the mounts conform to the engine’s movements.
John Smith, a Los Angeles-based car specialist and automotive writer, boasts over 20 years in the industry. With a background as a master technician and a decade-long writing stint at notable automotive publications, John now shares his expansive knowledge on CarFinite, simplifying car maintenance for readers.