If you hear something in your engine that appears to be making a knocking noise, this is something you will want to have checked immediately.

Fortunately, engine knocking is less common in modern vehicles because the engine timing is controlled by the vehicle’s computer. Driving an older vehicle does have advantages; however, avoiding engine knocking is not one of them. 

Hopefully, you will never have to experience the repair of your vehicle’s engine knocking. If this is something you encounter, you should consider how much this project could possibly cost you before committing to the repair.

There is no fixed pricing to repair your vehicle’s engine knocking. The repair often requires the use of octane boosters or refilling the tank with new fuel.

In the worst-case scenario, you will need to adjust the engine timing or replace the knock sensor. This would result in a repair cost of approximately $100 to $200.

The average engine knocking repair cost is approximately between $2,000 and $3,000. This is an average estimate and includes the combined costs of parts and labor. 

These price ranges do not include taxes and fees. They also do not include the specific vehicle or your location. To receive a more accurate estimate for your vehicle, you will need to contact a professional mechanic.

What is Engine Knocking?

Knocking heard coming from the vehicle’s engine could mean one of several different problems. However, the knocking sound usually occurs when the air-fuel mixture is not correct.

This causes the fuel to burn in disproportionate pockets rather than uniform bursts. Engine knocking must be repaired, or it can damage the piston as well as the cylinder wall. 

The knocking of the engine could possibly be caused by inadequate lubrication in the upper cylinder head area. This usually happens because the valves and lifters become loose and do not receive enough oil. 

Keep in mind that it is difficult to diagnose engine knocking; therefore, you might want to visit a professional mechanic to have a noise diagnosis performed.

This diagnosis usually costs between $88 and $144. Of course, additional funds will be required for the repairs.

Common Causes of Engine Knocking

Although most engine knocking issues are in relation to the engine’s inability to operate efficiently, there are other causes that will be discussed below. 

1. The Fuel Has a Low Octane Rating.

Filling your vehicle with a fuel that has an octane rating that is too low for your vehicle can cause engine knocking. Therefore, it is crucial that you use the appropriate fuel for your vehicle.

You can check the vehicle’s manual to verify the type of fuel recommended by the manufacturer. You might even find this information located on a sticker near the vehicle’s gas cap. 

In the United States, most vehicles should be fine with using 87 octane fuel; however, high-end and performance cars may require a fuel with a higher rating.

The Federal Trade Commission recommends switching to a fuel with a higher octane rating than recommended only if the intention is to attempt to alleviate engine knocking. 

You might even try purchasing an octane booster additive which can be purchased at your local auto parts store.

The octane booster additive will restore the correct octane rating, and this should eliminate the engine knocking. 

2. Carbon Deposits are Impeding the Efficient Burning of the Fuel.

It is a requirement that fuels contain a carbon cleaning detergent; however, they may fail to prevent carbon deposits from forming. Fuel is composed of many carbon molecules.

During the combustion process, the residual carbon will form on valves, spark plugs, and other components.

There are many special fuel injector cleaners and additives that are designed to clean carbon deposits on the vehicle’s engine components.

Using one of these cleaners or additives could resolve the engine knocking your vehicle is experiencing.

3. The Wrong Spark Plugs or an Incorrect Spark Plug Gap May be to Blame.

It is imperative that you only install the spark plugs that are recommended by the vehicle’s manufacturer.

Spark plugs withdraw heat from the combustion chamber; therefore, they have a certain heat range. When the wrong spark plugs are used, they fail to work correctly and cause engine knocking.  

Engine knocking can also be caused if the spark plug gap is set incorrectly. This gap is essential to igniting the air-fuel mixture that assists in powering the vehicle.

If the gap is too narrow, a spark that is too weak to complete the task will be created. If the gap is too wide, the spark may not fire or it could rapidly misfire.

Having the spark plugs replaced by a professional mechanic usually costs between $50 and $250. 

How to Correct the Engine Knocking Sound

Sometimes, it can be easy to fix the engine knocking sound your vehicle is experiencing. Therefore, there are a few things you can try before taking your vehicle to a professional mechanic for repair. 

Only use premium unleaded fuel in your vehicle

Low-grade fuel could be to blame for the engine knocking. Therefore, try to fill your vehicle with premium fuel, since it contains higher octane. The higher octane fuel can possibly repair your engine. 

Add a fuel detergent

Most fuels already contain a fuel detergent, but you may need something stronger to assist in alleviating the engine knocking. The correct fuel detergent could remove the carbon deposits from the fuel lines and eliminate the engine knocking. 

Replace incorrect or damaged spark plugs

Make sure the correct spark plugs are installed in your vehicle. You can verify the type of spark plugs recommended by the manufacturer in the vehicle’s manual

Should I Drive the Vehicle with Engine Knocking?

If you notice the engine knocking in your vehicle, it is recommended that you get it checked out as quickly as possible.

The engine is the heart of your vehicle; therefore, once you are aware of the engine knocking, the rod can fracture at any time without warning. This could happen the very next time you start your vehicle, or it could last for months.

However, if you try to ignore the problem, eventually the engine will get damaged, and you could end up stranded on the highway.

What Are Some Ways You Can Protect Your Engine From Harm?

You can protect your vehicle’s engine by providing routine maintenance and care for it. This will help protect all components of the vehicle and keep it in safe, working order.

Change the oil in your vehicle

Regular oil changes are a critical part of your vehicle’s maintenance and care. Make sure you keep oil changes current and up to date.

Check the vehicle’s cooling system regularly

The cooling system of your vehicle is critical to keeping the engine cool and working correctly. Keeping the vehicle’s engine cool will assist in keeping the engine from overheating which can cause engine damage such as knocking.

Change the vehicle’s air filter regularly

The air filter aids in keeping particles and debris from getting inside the engine and harming it.    

Change the vehicle’s fuel filter regularly

The fuel filter aids in keeping particles and debris from entering the engine and harming it.

Take care of the check engine light

If the check engine light is illuminated, it is recommended that you do not ignore it. It is in the best interest of your vehicle to have this checked out by a professional mechanic.

Should You Fix Engine Knocking in Your Vehicle?

If the issue that is causing the engine knock in your vehicle is a minor problem, making repairs should be rather inexpensive. Therefore, it is recommended that you try to get the repairs made, so you may continue driving your vehicle. 

If the issue that is causing the engine knock in your vehicle is a major problem, then you might consider not repairing your vehicle. If your vehicle is not valued for much money, you might want to reconsider the engine knocking repair. 

Engine Knocking Conclusion

If you notice a knocking sound coming from your vehicle’s engine, there are a couple of things you can try before seeking the help of a professional mechanic. 

If you try these things and you still hear the knocking sound, it is best to seek the advice of a professional mechanic.