What Does It Mean When Your Engine Is Knocking?

CashForYourJunkCar.org is an independent publisher. You will find affiliate links which means we may earn a commission if you purchase through these links. It doesn't cost you anything & it helps us keep the site running.

When your engine makes a distinctive noise, that’s an indication there’s a problem. Here’s what you need to know about your engine “knocking,” the possible causes, and how to prevent it.

Why Is My Car Making a Knocking Sound When I Drive?

There are various causes of a knocking sound when you drive, including the wrong fuel, faulty spark plugs, and carbon buildup. Engine knocking can be described as a pinging sound.

Causes of a Knocking Engine

Faulty Spark Plugs

Spark plugs are essential when it comes to starting your vehicle. These plugs are prone to wear, tear, and deterioration. Using the incorrect spark plugs can have the same effect on your vehicle as worn spark plugs. Using spark plugs that are too small or large or those that have gaps can cause your engine to make a knocking sound.

Using the Incorrect Octane Level

Gasoline is available at different octane levels. These levels are 87, 88-90, and 91-94. 87 octane is the lowest level of octane and standard for most vehicles. 88-90 octane levels are mid-grade, and 91-94 octane levels are premium. When you’re fueling your car, make sure you’re using the correct octane level.

Carbon Buildup

Your car produces carbon when fuel burns in the engine. As time progresses, carbon will continue to build up in the engine. When the carbon buildup collects in excessive amounts, your car’s fuel will be less effective and efficient. As a result, you may hear knocking sounds in your engine.

Overheating Engine

An overheating engine can cause abnormal combustion, causing engine knocking. Overheating engines can also cause other issues that can be minor or severe.

Incorrect Engine Timing

Newer model cars require precise engine timing, the time the spark plugs require to start. When spark plugs don’t begin at the proper time, multiple detonations in the cylinder can occur, causing you to experience a knocking sound in your engine.

How Do You Fix a Knocking Engine?

There are different things you can do to fix engine knocking sounds.

Increase Your Fuel Octane Levels

Before you fill your car’s gas tank, make sure you’re using the right fuel. The fuel you choose affects the engine’s performance. Using the wrong fuel can be a culprit of engine knocking. If you are driving a high-performance vehicle, it’s in your best interest to use 89 or 93 level octane. Although higher octane levels cost more, you will save tons of money on engine repairs in the future.

Check your owner’s manual. Using an octane level that is too low or too high for your vehicle can cause engine knocking and/or can damage your car’s engine.

Clean Your Combustion Chamber

If you’re using the correct octane for your vehicle, your spark plugs are the right size, and the engine is still knocking, the combustion chamber could be the problem. Use fuel additives to enhance your engine cleaning efforts. You can also flush your engine to improve its efficiency and stop the knocking sounds.

Keep an Eye on Your Engine’s Temperature

If you’ve tried the above methods and your engine continues to make a knocking sound, check your engine’s temperature. Make sure the electric fan is working correctly, so it continuously cools your engine. Make sure you’re using the proper coolant to help maintain a healthy engine.

Is an Engine Knock Dangerous?

Engine knocking is dangerous because it can severely damage your engine’s internal components. You don’t want to be driving, and suddenly your engine fails. The longer you drive your vehicle while it’s making a knocking noise, the further you damage your engine, causing expensive repairs.

What Is the Cost of Repairing a Knocking Engine?

Specific causes of engine knocking are more expensive than others to repair. If you address the knocking engine sound promptly, you may only have to pay a maximum of $200 for the repairs. Prolonging this repair can result in $3,000 worth of repairs or more.

Can You Drive a Car with Knocking Engine Sounds?

Driving a car with a knocking engine is not recommended. Continuing to drive your vehicle while it’s experiencing issues causes more problems and potentially worsens the current problems.

Is a Rod Knock Worth Fixing?

Yes, a rod knock is worth fixing. If you are experiencing this issue, you need to fix it immediately. When rod knock becomes a problem, this means the bearing is wholly or partially destroyed. The cause of a destroyed bearing is oil starvation. Without repairing rod knock, you’ll be operating your vehicle with broken parts, which is dangerous for you and other drivers.

A rod knock is a very different issue than an engine knock.

Can a Blown Head Gasket Cause Knocking?

Yes. If your engine is knocking, a blown head gasket could be the cause. These gaskets seal multiple vehicle fuels. When these gaskets blow, it can severely damage the engine and cause engine knocking.

What Are the Signs of Engine Knocking?

There are various signs of engine knocking, including:

  • The check engine light turning on
  • Your car making strange noises
  • Engine running inconsistently
  • Engine running roughly
  • Your vehicle produces oil patches
  • Smelling odors from inside the car
  • Your car is consuming more gas than normal
  • Smoke exiting from your exhaust

When your engine is knocking, don’t wait to resolve the issue. Waiting to repair your vehicle’s issues can result in more expensive repairs or having to junk your car. Regular car maintenance can help prevent extensive car repairs and replacements.