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NIGHTMARE: What is An Engine Knock?

NIGHTMARE: What is An Engine Knock?

If you’ve ever had a car that sounded like it had a few dice rolling around inside the engine, you’ve likely experienced an engine knock. Some call this spark or detonation knock. 

Engine knock is a severe issue for your vehicle. It’s not something you should take lightly or turn up the radio to ignore. You may not be able to fix it yourself, but it’s good to know more about it.

You need to know when to take your vehicle to a mechanic. Take some time now to learn more about engine knock and be a more confident vehicle owner moving forward. 

What Is An Engine Knock? 

When you’re grasping the concept of an engine knock, you have to exclude the sound of a rod knock or main bearing knock. They sound different and are unique issues. An engine knock sounds like a rhythmic or repetitive ping, tick, or tap inside your engine.

You’ll notice an increase in the intensity of the sound as you press the gas to go faster in your vehicle. 

What Causes An Engine to Knock? 

An engine knock is when two flame fronts collide inside the ignition chamber of one of your engine cylinders. This is the reason it makes the signature ping or tapping sound. 

Your spark plugs spark at a certain point in the movement of your piston. When there’s a hot spot inside your combustion chamber, there can be more than one spark occurring simultaneously. This causes an excess of pressure inside the combustion chamber. 

Pro Tip: Have you ever heard the phrase “engine threw a rod?” We uncovered what exactly it means.

Mechanic repairing engine on vehicle
Keep an ear out for a rhythmic or repetitive ping, tick, or tap sound inside your engine.

Does Low Oil Cause Engine Knocking?

Low oil can cause an engine to knock, but it’s a different sound. When you run the engine without enough lubricant inside, many things could go wrong. 

A knock from low oil will sound more like a “knock” and less like a “tick” under the hood. If you hear this sound, you can try checking your oil levels first. However, hearing a thumping or tapping sound within your engine is always a sign of mechanical trouble. 

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What Does Engine Knock Feel Like?

You may not feel much difference when driving a vehicle with an engine knock. Take notice if your engine is underperforming or not as responsive as usual. The sound the knock produces is more critical than the feel of the vehicle. Don’t worry, though; you’ll hear it. 

Can Engine Knock Be Fixed? 

A mechanic should be able to fix a combustion “knock” pretty simply. Any trained mechanic will know how to troubleshoot to narrow down the reason for your engine knock. 

There are many reasons you could end up hearing your engine clicking or ticking. Low octane fuel is the most common reason your engine might be experiencing combustion issues. You may have a clogged fuel injector or a leak in your air intake. An unsavory mixture of air and fuel inside the combustion chamber can also cause a knock. 

How Do You Stop This Problem?

Ultimately, you stop engine knock by fixing the underlying problem. Restoring the proper air-fuel mixture, so the heat and combustion inside the chamber evenly disperse will solve the problem. 

How do you do that? Well, there are a few answers. 

You can use a higher octane fuel. You can change your spark plugs to see if their spark was the problem or take your vehicle to a mechanic to diagnose and rectify the issue. It’s probably best to try the simple remedies first, as they are much more affordable. 

Two mechanic checking engine
To stop engine knock you will need to restore the proper air-fuel mixture.

How Much Does It Cost to Fix? 

Finding the source of the problem might be the easiest part of fixing the engine knock. However, taking a car to the shop means your mechanic is in for quite an extensive job. Diagnosis alone could take hours of work. 

After that, your mechanic may have to venture into the inner workings of your engine. If they have to take the engine apart, the cost will rise quickly. Depending on the reason for the knock, the cost of fixing the issue could range anywhere from a couple of hundred dollars to $2,000-$3,000. 

Does Engine Knock Cause Damage?

Leaving an engine knock unattended can cause severe damage to your engine. Detonation knocks can melt your spark plugs, crack your piston rings, crack your pistons, mess up rod bearings, and even blow a head gasket. 

Now that you know a little more about the cause and source of this issue, you can more appropriately respond if you encounter it. Remember, arming yourself with knowledge can save you a lot of money throughout your life. Never stop trying to figure it out, but don’t assume you’re a mechanic without proper training.

Have you ever experienced an engine knock? Tell us your experience in the comments!

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