What Does Engine Knock Sound Like? Causes And Fix

December 10, 2022 by No Comments

You should never experience a knocking engine because it can harm your engine severely. Here’s how to identify an engine knock and what might be causing it.

What Does Engine Knock Sound Like?

When you accelerate, the engine knock sounds like someone is sitting and banging on your engine block with a metal hammer. Engine knocking or pinging is most likely the source of a knocking sound you only hear when accelerating.

How Do You Know If Your Engine is Knocking?

You might have probably heard or read the term “engine knocking” before since mechanics and car experts usually use it, but it can be confusing since an engine can give off many unusual sounds if it is experiencing some problem. There may be some grinding, ticking, tapping, squeaking, or clicking sounds. This may prompt you to wonder what engine knocking sounds like.

The term “engine knocking sound” typically refers to a metallic pinging noise that is somewhat akin to the sound made when metal balls or objects are shaken inside a tin can. Engine knocking can also sound like a rattle that gets worse and vibrates poorly. It sounds like marbles stuck in a blender when you turn your car’s engine on. During acceleration, while going uphill, or while the engine is idle, you might hear it.

When you notice an engine knocking, you just don’t ask, “what does engine knocking sound like?”, and ignore it. The moment you notice this metallic pinging or tapping sound, it is crucial that you get it fixed as soon as you can. This is due to the fact that engine knocking is a sign that something is wrong either inside your engine or during the combustion process. If you ignore it and act as if you didn’t hear anything, the issue could quickly get worse and end up costing a lot of money to fix.

How can you tell if your engine is knocking, you may ask? If you hear the metallic sound, you’ll know. Instead of the sweet engine purr, you will now hear a constant pinging or tapping sound that gets louder and faster as you press the gas pedal. However, the sounds you hear can change depending on what made the engine start to knock.

What Happens When a Car Engine Knocks?

Describe the sound of an engine knocking. What occurs when your car’s engine knocks? You must comprehend how an engine functions in order to comprehend what happens to your car when it knocks.

Each of the four movements that a piston makes in a four-cycle engine involves moving parts that are interdependent. When you turn the key in the ignition or press the car’s start button, the battery in the car uses its stored energy to drive the starter, which turns the crankshaft. This crankshaft can access the necessary lubrication because it is exposed to the oil at the bottom of the engine.

The main bearings, connecting rods, connecting rod bearings, end bushings, pistons, rings, and cylinders are all lubricated with oil as the crankshaft rotates. Since it is in charge of the intake, compression, combustion, and exhaust, the aforementioned rotation is essential. The crankshaft causes the pistons to move, and it also permits the intake and exhaust camshafts or shafts to rotate.

Contrarily, the camshaft controls whether or not the intake or exhaust valves are open. Either directly moving the valve stem or using valve lifters attached to the adjustable pushrods and rocker arm are used to accomplish this. When the rocker or cam is not pressing the valve open, each valve stem will pass through a coil spring that closes the valve. An oil seal is present on each valve shaft, which aids in preventing oil from entering the combustion chamber. Keep in mind that the oil in the oil pan reservoir is what lubricates the engine’s entire moving parts.

As a result, if you hear an engine knocking or any other unusual noises, it may be a sign that there is a problem with the engine or the combustion process. The engine’s poor timing is a common cause of knocking. The engine, as was already mentioned, has a lot of moving parts that work together. This procedure ought to go without a hitch. When there is improper timing, the engine’s parts are not functioning as they should. It indicates improper ignition, which can result in engine knocking.

When there are some mechanical problems with the engine, engine knocking can also occur. It is good that you are asking, “what does engine knocking sound like?”. It’s because you need to know how to recognize it so you can identify the symptoms right away. It is necessary because different knocks can produce different sounds, and you need to be able to identify a particular sound in order to understand what caused it and how to fix it.

What Causes the Tapping Sound in the Engine?

We have answered the question, “what does engine knocking sound like?”, but you might want to know what causes the knocking or tapping sound in the engine. Knowing what is causing the engine to knock will give you an idea of how to fix it or stop it from happening in the future.

The most typical causes of engine knocking are the issues listed below, along with solutions.

Low octane fuel.

what does engine knock sound like

The fuel and air mixture may ignite too early and cause a detonation knock if you use fuel with a lower octane value than that advised for your car. This results in the engine knocking noise.

It’s crucial that you adhere to the fuel recommendations made by your car’s manufacturer, including the octane rating. Recognize that the fuel will have a higher octane percentage and higher octane rating. It won’t likely ignite too soon because the detonation will be more carefully controlled when it is used.

Carbon deposits.

There is a cleaning agent present in many of the fuels that are used today that can remove carbon buildup that has already occurred. This cleaning agent is unable to stop the carbon deposits from forming, as helpful as they are. This is due to the fact that carbon will always be a byproduct of burning fuel. The cylinder may become more crowded as a result of the carbon, which may increase compression and cause a knocking sound. Fortunately, you can solve this issue by removing the carbon sludge from various engine components by using a specialized fuel injector additive or cleaner.

Worn bearings.

Rod knock can also be caused by worn bearings. Since the pistons in the car’s engine block move up and down, this is possible. In turn, the crankshaft is turned by these pistons, which propels the vehicle forward by supplying power to the wheels. The rod bearings help the pistons move, and when they begin to wear out, the pistons will start to knock against the crankshaft and make engine knocking noises. You’ll need to replace the bearings, make some repairs to the crankshaft, and replace the pistons to solve the issue.

Faulty spark plugs.

The spark that ignites the fuel and air mixture in the combustion chamber and starts the engine’s power stroke is produced by the spark plugs. An engine knock may be caused by faulty spark plugs or ones with incorrect gaps or spacing. This may occur because different types of spark plugs have different heat tolerances, which may result in detonation knock or premature detonation. The fuel/air mixture won’t ignite if the gap is too small because the spark won’t be strong enough. However, if the gap is too wide, the plug might not even spark. Use the proper spark plugs or swap out the damaged ones to fix this.

a mixture of lean air and fuel.

Combustion occurs when a spark ignites the fuel/compressed air mixture. The aforementioned mixture, though, will turn lean if there is too much oxygen present. It denotes that there is not enough fuel in the mixture to burn quickly, which can result in multiple detonations and engine-knocking noises. Your cylinder walls and pistons may get damaged if the issue is left unattended if it persists.

This issue is brought on by malfunctioning engine parts in charge of regulating or controlling the flow of both fuel and air. You must make sure that the mass airflow and oxygen sensors in your car are functioning properly if you want to resolve this issue. Additionally, you must check your fuel pump and injectors for any signs of wear or damage.

Bad knock sensors.

Engine knocking can also be caused by a faulty knock sensor. This is possible because your engine’s knock sensor is in charge of identifying any knocking problems that might arise. If a malfunctioning knock sensor is unable to recognize this, the engine will knock without warning.

Modern cars are fitted with a variety of sensors. From the timing to the air/fuel ratio, it is their job to make sure everything runs smoothly. You won’t need to manually adjust the timing because the air/fuel mixture will be adjusted by the car’s computer when these sensors detect some knocking issues. Engine knocking will therefore happen if these sensors malfunction.

You’ll need to use an OBD II scanner tool to scan your car in order to identify the issue and fix it. If your knock sensor is broken, you should get a new one. Once repaired, your vehicle ought to automatically adjust the timing and the air/fuel ratio. Once any error codes have been removed, you can wait to see if a problem will recur. If there isn’t, the issue has already been resolved.

what does engine knock sound like

Bad timing.

Another thing that can cause engine knocking, which can lead you to ask “what does engine knocking sound like?”, is bad timing. It denotes improper ignition timing. This time period is referred to as the precise moment when the fuel is ignited by the spark plugs.

Precise timing is essential for maximizing the car’s efficiency, and the onboard computer of the vehicle controls this. It can lead to uneven fuel burning, multiple explosions in the cylinders, and the engine knocking if the timing is off and the spark plugs are not firing at the proper time.

This issue needs to be checked out right away if you notice it. The issue will worsen if you ignore this timing issue and the engine continues to knock excessively. Your engine could get harmed, or you might run into issues that require pricey repairs. You can bring your car to an auto repair shop and have a specialist change the timing for you.

How to Fix Engine Knock?

Now that you are aware of the various potential causes of engine knock, you probably want to know how to fix it.

You need to consider when the knocking first started. It’s likely that the fuel in your tank is contaminated if it occurred after you refueled the vehicle. You need to either replace the fuel or try using an octane booster to fix this.

A diagnostic scanner can be used to check for any error codes connected to the knock sensor or sensors. It is definitely time to repair the wiring or replace the knock sensor if you discover any trouble codes related to it.

To ensure that you use the proper spark plug type for your particular car engine, you should also check the spark plugs. To choose the proper spark plugs, consult your repair manual.

You should definitely check and adjust the ignition timing if your car is older or has an adjustable ignition timing system. To determine whether you have adjustable timing or not, consult your repair manual.

If you are unfamiliar with timing adjustments, let a repair shop handle it since the process also requires some specialized tools.


How Do You Stop Engine Knocking?

Making sure you have fuel with the appropriate octane rating for your car model is the first step to stopping engine knocking. To make it less sensitive to detonations, you might try using an octane booster.

How Much Does It Cost to Fix An Engine Knock?

The cost to repair an engine knock is not set. Often, all you need to do is add octane boosters or new fuel to the tank. In the worst case, you will need to replace the knock sensor or adjust the ignition timing. However, you should budget between $100 and $200.

Can You Drive a Car With a Knocking Engine?

Driving a car that is knocking is not advised. If you don’t take precautions, engine knock, also known as “detonation,” can cause serious damage to your engine’s internal components and cost you more than $3,000 in repairs.

Can Low Oil Cause Engine Knock?

The ignition timing or engine knocking of your car’s engine has nothing to do with the engine oil. If you have such a low engine oil level, it is probably the reason why the engine has low oil pressure, though it might have an indirect impact.