Engine Soundproofing Blanket: Do They Actually Work?

engine soundproofing blanket

Last updated: March 11, 2022 at 8:31 am

Engine soundproofing blankets are just as their name describes, a blanket for your car engine. The reason behind them is to break up and dampen any loud sounds coming from the engine which helps in soundproofing a car. If installed correctly, they should reduce engine noise by around 50% but do come with some negatives.

In this article:

We will look at the intended purpose and use of soundproof engine blankets, alternatives, and if they work as advertised.

What Is an Engine Soundproofing Blanket?

Engine soundproofing blankets are designed to acoustically absorb and insulate against noise, vibration, and heat.

An engine soundproofing blanket can be fabricated into custom sizes and shapes by cutting the material with a sharp knife or scissors to meet specific application requirements.

Most blankets are easy to install and come with grommets or zip ties so they can be attached to the engine easily. They can usually be folded back when not needed or to let the engine cool.

How Effective Are They?

Engine soundproofing blankets can reduce engine noise by up to 50%. In addition to reducing engine noise, these blankets also reduce heat levels in the engine bay. This can increase overall performance since your engine can operate at full power without overheating.

There are a lot of factors that go into how much noise reduction you get with an engine blanket.

For starters, the quality of the materials used in the blanket makes a huge difference. Using a high quality fibreglass and rubber compound will give you better results than a cheap fibreglass and Styrofoam.

The next factor is how well the blanket fits around the engine and if it’s covering all of the components that create noise. Like the:

  • radiator
  • alternator
  • and starter motor

A blanket is only going to be effective if it’s fitted properly. If it doesn’t cover all the above components, you’ll still have exposure to engine noise.

Lastly, a large part of how effective an engine blanket is depends on what type of car you have and the insulation already installed. Some cars are better insulated than others as standard – but that doesn’t mean you can’t get more done aftermarket.

How Do They Work?

Engine soundproofing are generally made from woven fabric and acoustically transparent material. This allows sound waves to pass through the outer layer to reach the secondary, soundproof material.

These layers absorb and dissipate the sound waves, transforming them into heat energy that won’t bounce back. Some blankets also include a layer of mass loaded vinyl that helps minimise noise transfer even further.

engine blanket being installed

Why Use an Engine Blanket?

Engine blankets are more effective than other products because they provide multi-layer protection against engine noise.

These blankets wrap around the entire engine block, which means they can insulate against noise in multiple directions. As a result, less noise escapes from all sides of the engine block, making for a quieter ride for everyone on board.

The pre-cut design of these blankets makes installation easier than it is with bulkier insulation products like foam blocks and fibreglass panels, which require cutting tools to size them properly.

Engine blankets are also lighter and easier to lift than traditional insulation materials. Thus, making them easier to install in hard-to-reach places, where there’s limited room to manoeuvre.

Also read: 5 Ways to Reduce Diesel Engine Noise

What Are the Downsides?

The main reason people get engine compartment insulation is to reduce noise. This is especially important if you drive a sports car that has a loud aftermarket exhaust system.

However, there are several downsides to getting a blanket for your engine.

First, it can cause your engine to overheat. Having an extra layer of insulation will block some of the heat from escaping from under the hood. If your engine gets too hot, it can cause serious damage and reduce performance.

Second, it can block air from reaching other components in the engine compartment, like the alternator or radiator fan. These parts need a steady flow of cool air to function properly.

Likewise, they may be expensive. While these blankets may be worth their price tag if your goal is simply noise reduction, it may not be worth it if cost is a major concern for you.

It is important to consider how much money you’ll spend on both installation costs and maintenance before deciding whether a blanket is right for you.

4 Engine Soundproofing Alternatives

Soundproof engine blankets are an effective way to reduce engine noise in your car. However, they can be cumbersome and expensive. Here are four other ways you can reduce the noise from your engine using soundproofing techniques:

1. Acoustic Hood Liners

acoustic hood liner

If there isn’t room for an engine blanket or you would like to add additional sound dampening to your car, consider using an acoustic hood liner.

This is thick padding that’s placed inside the hood and is designed to absorb noise in the same way as a soundproof engine blanket, but without as much hassle in terms of fitting it over the engine.

An added benefit of using an acoustic hood liner is that it will help protect your car from heat damage since it will absorb some of the heat coming from the engine.

Most car manufacturers include a hood liner as part of their cars to prevent damage from occurring during normal operation.

Keep in mind that some cars may not be compatible with hood liners because they don’t have enough room in the engine bay for one to fit.

2. Replacing Your Exhaust System

If you have a conventional muffler, replacing it with a glass pack muffler or a turbo muffler is one way to improve engine noise reduction significantly. A glass pack-style muffler will use steel wool or ceramic packing material to absorb sound waves and deaden the sound of your engine.

Turbo-style mufflers will use a perforated baffle right after the catalytic converter that forces the exhaust flow to expand laterally, which absorbs the sound waves before they reach the tailpipe.

Newer mufflers also use fibreglass insulation inside the casing so that noise is absorbed as it travels through the pipe. Most of these new technologies were developed specifically with quieter engines in mind, which makes them great alternatives to engine soundproofing blankets.

3. Replace or Repair Head Gasket

replace head gasket

Head gaskets can be damaged by heat and vibration over time. If a gasket has deteriorated, it can cause an air leak which produces a whistling sound. To eliminate this whistling noise, you need to remove the damaged gasket

Perforated sheet metal can also deteriorate over time and lose its shape. This can cause a whistling sound when air passes through the perforations. To eliminate this problem, you need to flatten out the sheet metal to restore its original shape.

In addition to replacing old gaskets, you may also have to replace sheet metal if it has rusted or been punctured. This is caused by holes and rust.

4. Add New Rubber Window Seals

Many people overlook window seals as they age, causing them to dry out, crack and fall apart.

These window seals are designed to protect windows from wind and water leaks. But, they also serve an important role in reducing the amount of noise that enters your car.

To eliminate engine noise with this method, you must use a high-quality rubber sealant to attach new seals around the perimeter of each window. You may want to consider using an aftermarket sealant if your car is more than 10 years old.

Rounding Up

Engine soundproofing blankets are kind of like a one-size-fits-most approach to reducing car noise. The results from using such a blanket will vary from car to car, based on factors such as the engine’s make, power, size, and so on. But, we’d expect to see around a 50% decrease in engine noise.

They do come with downsides, however, like overheating. So weigh up if reducing engine noise is worth it for you. It may also be beneficial to try alternatives first and measure the noise difference.

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About the Author: AJ

AJ is a self-confessed soundproofing nut. He has written full-time on Quiet Living for the past 3 years, and has a wealth of knowledge about living a quieter life, soundproofing and fixing loud noises.

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