When it comes to vehicle performance and smooth operation, engine mounts (also called motor mounts) play a crucial role. These often-overlooked components secure your car’s engine to the chassis, minimizing vibrations and movement. But what happens when a motor mount fails? Let’s break down everything you need to know about motor mounts, including bad motor mount symptoms, engine mount replacement, and how to handle issues yourself.
What is an Engine Mount?
An engine mount is a sturdy component designed to hold the engine in place and absorb vibrations and movement caused by the running engine. It consists of a metal bracket and a rubber or hydraulic-filled insert, which dampens engine vibrations and prevents excessive movement that could damage surrounding components.
Most vehicles have three to four motor mounts, depending on the engine layout and size. If one or more of these mounts become damaged, it can lead to rough idling, excessive vibrations, and even potential engine damage.
How Does an Engine Mount Work?
Engine mounts work as a buffer between the engine and the vehicle frame, ensuring a smooth driving experience. Here’s how they function:
- Securing the Engine: The mount holds the engine firmly in place, preventing excessive movement during acceleration and braking.
- Absorbing Vibrations: The rubber or hydraulic filling in the mount helps dampen the vibrations generated by the engine.
- Reducing Noise: A properly functioning motor mount minimizes engine noise inside the cabin, making for a more comfortable ride.
- Enhancing Safety: By keeping the engine in position, mounts help prevent misalignment of other critical components, such as the exhaust system and transmission.
Types of Engine Mounts
Different vehicles use different types of motor mounts, each with its unique advantages. Here are the most common types:
1. Rubber Motor Mounts
- Most common type in older vehicles.
- Made of metal brackets with rubber inserts.
- Excellent at reducing vibrations but may wear out over time.
2. Hydraulic Motor Mounts
- Found in many modern vehicles.
- Filled with hydraulic fluid to absorb more vibrations.
- More durable than rubber mounts but more expensive to replace.
3. Active Engine Mounts
- Advanced mounts that use electronic or vacuum-controlled mechanisms.
- Can adjust damping properties based on engine RPM and driving conditions.
- Typically found in luxury or performance vehicles.
4. Polyurethane Motor Mounts
- Used in performance and racing vehicles.
- More rigid than rubber mounts, leading to increased vibration but better power transfer.
- Highly durable but can make the ride rougher.
Common Causes of Motor Mount Failure
Like any vehicle component, motor mounts wear out over time. Some of the most common causes of failure include:
- Age and Wear: Rubber mounts deteriorate over time, leading to cracks and weakness.
- Engine Torque and Vibration: High torque and constant engine movement can strain mounts, especially in performance cars.
- Oil Leaks: Engine oil leaking onto the mounts can degrade rubber and cause premature failure.
- Harsh Driving Conditions: Rough roads, excessive braking, and aggressive driving can put extra stress on the mounts.
- Improper Installation: Poorly installed mounts may not align correctly, causing uneven wear and early failure.
Signs of a Bad Motor Mount
If your vehicle is experiencing engine vibration or unusual movements, you might have a bad motor mount. Here are some common symptoms to watch for:
- Excessive Engine Vibration: More shaking and movement than usual, especially at idle.
- Clunking or Banging Noises: A loud clunk when accelerating or shifting gears can indicate a broken mount.
- Engine Movement: Visible shifting of the engine under the hood when revving or driving.
- Rough Idling: The car may feel unstable when stopped due to poor vibration absorption.
- Increased Cabin Noise: More noise and rattling inside the vehicle, especially at high RPMs.
When to Replace an Engine Mount
On average, motor mounts last between 60,000 and 100,000 miles. However, this can vary based on driving habits, road conditions, and engine stress. If you notice any of the above symptoms, it’s best to inspect the mounts immediately and replace them if needed to prevent further damage.
Engine Mount Replacement Cost
The cost to replace a motor mount varies depending on the vehicle model and mount type:
- Parts Only: $50 – $250 per mount
- Labor Costs: $150 – $450
- Total Replacement Cost: $200 – $700
Some performance or specialty vehicles may have higher costs due to complex engine layouts.
DIY Guide: How to Replace a Motor Mount
If you’re comfortable working on your vehicle, you can replace a bad motor mount at home. Here’s how:
Tools and Supplies Needed
- New engine mount
- Wrench and socket set
- Jack and jack stands
- Pry bar
- Torque wrench
- Thread locker (optional for securing bolts)
- Safety gloves and goggles
Step-by-Step Replacement Process
- Disconnect the Battery: Safety first—disconnect the negative terminal.
- Lift the Engine Slightly: Use a jack with a block of wood under the oil pan to support the engine.
- Remove the Old Mount: Unbolt the mount from the frame and engine block.
- Install the New Mount: Align the new mount and bolt it into place.
- Torque the Bolts to Spec: Check your vehicle’s manual for proper torque settings.
- Lower the Engine and Reconnect Battery: Once secured, carefully lower the engine and reconnect the battery.
If you’re unsure, it’s best to have a professional handle the replacement.
Additional Parts and Consumables
When replacing an engine mount, consider inspecting and replacing these related components:
- Transmission mounts (if worn out)
- Bolts and fasteners (if rusted or damaged)
- Engine dampers (for extra vibration control)
- Thread locker (to secure bolts and prevent loosening)
Final Thoughts
A motor mount may seem like a small part, but it plays a big role in vehicle performance and comfort. Recognizing bad motor mount symptoms early and performing timely engine mount replacement can prevent costly repairs and keep your car running smoothly.
