Motor mounts are crucial components that secure your engine to the vehicle’s frame while absorbing vibrations. They keep the engine stable, reduce noise, and prevent excessive movement that could damage other parts. But like any part, motor mounts can wear out and fail over time. So, how do motor mounts go bad? Let’s explore the common causes, symptoms, and what you can do to keep your engine mounts in good shape.
What Are Motor Mounts and Why Are They Important?
Motor mounts typically consist of a metal bracket and a rubber or hydraulic component that cushions the engine. Their job is to hold the engine firmly in place while absorbing shocks and vibrations caused by engine movement and road conditions. When motor mounts fail, the engine can shift excessively, causing vibrations, noises, and even damage to hoses and belts.
Common Causes of Motor Mount Failure
1. Age and Wear Over Time
Motor mounts naturally deteriorate as your car ages. The rubber components lose elasticity, crack, and become brittle due to constant exposure to heat, cold, and engine vibrations. Fluid-filled (hydraulic) mounts can develop leaks, reducing their ability to dampen vibrations. This wear and tear is the most common reason for motor mount failure, especially in vehicles with high mileage.
2. Exposure to Heat and Chemicals
Heat from the engine and exhaust manifold can cause the rubber in motor mounts to dry out and crack. Additionally, oil or other fluid leaks from the engine can accelerate rubber deterioration. For example, leaking valve cover oil dripping onto mounts can cause them to wear out prematurely.
3. Poor Driving Habits
Aggressive driving behaviors such as hard launches, rapid acceleration, harsh braking, and improper clutch use (in manual transmissions) place extra stress on motor mounts. Over-revving the engine or frequent burnouts can cause mounts to fail sooner than expected.
4. Improper Installation or Defective Parts
If motor mounts are not installed correctly or if low-quality aftermarket mounts are used, they may fail prematurely. Sometimes, only one mount is replaced while others remain worn, causing uneven stress and early failure. Also, mounts that lack proper heat shielding or are made with inferior materials can deteriorate faster.
5. Vehicle Damage and Road Hazards
Accidents or impacts, such as hitting potholes or raised railroad crossings at high speed, can damage motor mounts or bend the vehicle’s frame, putting extra strain on them. This can lead to cracks or breaks in the mounts and cause engine misalignment.
Signs Your Motor Mounts Are Going Bad
Recognizing the symptoms early can save you from costly repairs down the road.
– Excessive Engine Vibrations: You may feel strong vibrations inside the cabin, especially when idling, accelerating, or starting the engine. This happens because worn mounts no longer absorb engine movement effectively.
– Unusual Noises: Thumping, clunking, rattling, or banging noises coming from under the hood often indicate that the engine is moving excessively and hitting other parts.
– Visible Engine Movement: When you open the hood and rev the engine, the engine should not shift more than 1-2 inches. Excessive rocking or sagging of the engine is a clear sign of bad mounts.
– Engine Misalignment: The engine may appear tilted or sagging to one side, which can cause strain on hoses and belts, leading to leaks or breaks.
– Fluid Leaks or Cracks on Mounts: Inspect the mounts for cracks in the rubber, corrosion on metal parts, or leaking fluid from hydraulic mounts. Any visible damage means the mounts are compromised.
How to Prevent Motor Mount Failure
– Drive Smoothly: Avoid aggressive driving, hard launches, and rapid gear changes to reduce stress on mounts.
– Regular Inspections: Have your motor mounts checked during routine maintenance, especially if your vehicle has high mileage.
– Address Fluid Leaks Promptly: Fix any oil or coolant leaks that could drip onto mounts and accelerate wear.
– Use Quality Parts and Proper Installation: Always opt for OEM or high-quality mounts and have them installed by a reputable mechanic.
– Check After Accidents: If your vehicle has been in a collision, have the mounts and frame inspected for damage.
Replacing motor mounts when they show signs of failure is critical to maintaining engine stability and preventing further damage.
Motor mounts go bad mainly due to age, heat exposure, driving habits, improper installation, and accidents. Keeping an eye out for vibration, noise, and visible engine movement can help you catch problems early and keep your engine running smoothly.