What is an Engine Mount & Why Does it Matter in Your Car?

Key Highlights:

• Engine mounts often top the list of most neglected, crucial components in a car.
• The cost of engine mount replacements greatly depends on how easy they are to access.
• Even EVs, despite lacking engines in the traditional sense, use specially designed mounts.

What do Engine Mounts do?

Secures the engine

The engine is a heavy part of the vehicle. Engine mounts are designed to hold the engine securely in a fixed position under the bonnet. This helps prevent any unwanted movement while driving, braking or turning.

Reduces vibrations

Internal combustion engines produce significant vibrations because of their many moving parts. Engine mounts are designed to absorb most of these vibrations, preventing them from reaching the cabin. This helps provide a more comfortable experience for both the driver and passengers.

Protects connected parts

The engine is linked to several systems such as the exhaust, cooling system and drivetrain. If the engine moves excessively, it could damage these connected components. Engine mounts ensure that everything stays properly aligned and functions as intended.

Enhances crash safety

In the event of an accident, particularly a frontal collision, engine mounts can be engineered to break in a controlled manner. This helps direct the engine beneath the passenger cabin instead of pushing it into the cabin, thereby enhancing crash safety.

Types of Engine Mounts

Rubber Mounts

Typically made using a mix of metal and rubber, they are cost-effective and have a basic design.

Hydraulic Mounts

A fluid-filled chamber helps absorb vibrations more effectively. As the fluid moves within the mount, Noise Vibration Harshness (NVH) levels are brought down drastically. Hydraulic mounts are typically found in luxury vehicles.

Electronic or Active Mounts

These rely on sensors and actuators to modify the stiffness of the mount based on engine speed or changing road conditions. They offer the highest level of comfort, but this comes at a substantial cost, both initially and in ongoing maintenance.

Vacuum-Controlled Mounts

Predominantly found in diesel vehicles, they use engine vacuum to alter dampening. They are designed to provide a good mix of comfort and control, based on engine RPM.

How Engine Mounts Work

An engine mount usually has two metal plates with a rubber or fluid-filled section in between. One plate is attached to the engine while the other is fixed to the vehicle's frame. When the engine operates, the rubber or fluid section cushions it by absorbing most of the motion. In more advanced versions, sensors monitor the engine's behaviour and adjust the stiffness of the mount to ensure optimal performance.

Signs of a Failing Engine Mount

Engine mounts are not designed to last the life of a car. With time, they can deteriorate due to constant exposure to heat, engine vibrations, and varying road conditions. Here are some signs that indicate a potential engine mount failure:

Excessive Vibrations

If you notice strong vibrations in the steering wheel or within the cabin, particularly while the engine is idling, one of the engine mounts may be worn out.

Engine Movement

If the engine shakes excessively while starting the car or during gear changes, it is a sign that a mount may be loose or damaged.

Clunking or Banging

Worn mounts can cause metal parts to come into direct contact with each other. This often results in clunking noises, especially when the vehicle accelerates or slows down.

Misaligned Components

If a damaged mount causes the engine to shift from its original position, it can slightly shift the position of hoses, wires and various other components.

How to Take Care of Engine Mounts

Although engine mounts are not something you can service regularly like an oil change, there are ways to extend their life. Let us discuss some of them:

Drive Smoothly

As applicable to any other automotive component, gentle driving habits guarantee a long life for engine mounts.

Inspect Regularly

During routine servicing, request your mechanic to check the engine mounts for any signs of wear or damage.

Replace when Needed

If a mount is worn out or broken, it should be replaced immediately. Continuing to drive with damaged mounts can lead to further strain in other engine components and may compromise the safety of the vehicle.

Avoid Fluid Leaks

For hydraulic or fluid-filled mounts, it is important to check for any leaks. The slightest leak can drastically reduce performance.

Use Quality Parts

If a mount needs to be replaced, it is best to use parts that are recommended by the vehicle manufacturer. Inexpensive alternatives might not provide the same level of durability or performance.

Innovations in Engine Mount Technology

Engine mount technology has significantly evolved over the past few decades. Modern vehicles, particularly luxury and high-performance cars, are equipped with advanced variants such as the ones below:

Active Engine Mounts

Actuators and ECUs adjust dampening as needed. For instance, they can become firmer during aggressive driving and more flexible during city driving. This helps enhance both ride comfort and overall performance.

Adaptive Hydraulic Mounts

Employ a combination of fluid damping and electronically controlled valves. The valves adjust the flow of fluid inside the mount according to driving conditions.

Magnetorheological Engine Mounts

These are filled with a special fluid that can change its viscosity when exposed to magnetic fields. This feature enables the mount to react immediately to changes in engine behaviour.

Smart Mounts

Certain engine mounts come with sensors that track engine movement and vibrations in real time. ECU can utilise the collected information to improve engine performance, enhance fuel efficiency and reduce emissions.

Mounts in Electric Vehicles

Electric vehicles also require mounts (often referred to as just ‘engine mounts,’ ironically), although their needs differ from those of traditional engines. Since EVs have fewer moving components and produce less vibration, the primary role of their mounts is to isolate noise rather than reduce vibration. These mounts are also specifically designed to handle the unique high-initial-torque characteristics of electric motors.

In certain premium electric cars, active mounts are used to stabilise the motor during sudden torque surges. With the continued rise of EV adoption, innovations in mount design are inevitable.

Cost of Replacing Engine Mounts

The cost of replacing an engine mount depends on the type of mount and the specific make and model. Typically, rubber mounts are the most affordable to replace. Hydraulic and electronic mounts tend to be costlier because of their complex design. Labour charges can also be high if the mount is located in an area that is difficult to access.

In India, for a regular vehicle, replacing a basic engine mount generally costs between ₹1,500 and ₹5,000. For premium vehicles that use active mounts, the cost per mount can go up to ₹25,000 or even higher.

FAQs

1. How many engine mounts does a car typically have?
Most cars have three to four engine mounts.

2. What materials are engine mounts made of?
Engine mounts are usually made of metal and rubber. Some newer types use hydraulic or electronic components.

3. What are the signs of a bad engine mount?
Common signs include excessive engine vibration, clunking noises, and engine movement when accelerating.

4. Can I drive with a bad engine mount?
It is possible but not recommended, as it can cause further damage to the engine and transmission.

5. How long do engine mounts last?
Typically, engine mounts last between five to seven years, depending on driving habits and road conditions.