How Long Can You Drive A Car With A Knocking Engine? (Explained)

Your car’s engine generates a loud bang or a frightening noise, which is the knocking sound. This has an impact on your driving. I’m sure you’ll be concerned about it and will always consider the cost of repair. Can you drive a car with a knocking engine, though? Is it risky for you if your car’s engine is not fixed in a timely manner?

This is dependent on the sound of your engine. They can get smaller or larger; if they get smaller, don’t panic; you’ll be able to keep jogging for several months to years.

However, if the noise gets worse the following time, it’s necessary to get your automobile serviced. Your engine may be severely damaged if the knock is extremely loud.

In the previous article, we talked about rattling sounds. And now we’ll show you the causes of your engine knocking, answer the title question, and offer the best ways to assist you to solve the problem in this article.

Rod Knock Symptoms

Rod knocking is a symptom that you may already be aware of. Though you may notice additional symptoms, the knocking noise made by the rod is the predominant sign and one that can be clearly identified.

A sequence of clanking and banging noises emanating from your engine can be easily identified as a rod knock. When you crank the engine and then take off the gas, you should be able to hear this sound more clearly.

This is because your engine will not be using gas at this time. As a result, the engine’s sound is muffled, leaving you with a clear route for the sound of rod knock.

You’ll most likely hear this noise right after you take off the throttle, and if you do, you’re in for a lot of problems.

Causes of a Knocking Car Engine

Sensor for a Bad Knock

A faulty knock sensor is the most prevalent cause of engine knock. The knock sensor is designed specifically to prevent engine knocks.

The engine control system continuously strives for the most advanced ignition available in order to maximize performance. If you fill your tank with low-octane fuel, your engine will require more retarded ignition time to avoid engine knock.

As a result, the engine knock sensors’ function is to keep an eye out for any knocks and, if one is detected, to signal the engine to slow down the ignition even further to avoid engine damage. If this engine knock sensor fails, it can transmit incorrect signals to the engine control unit, resulting in an engine knock.

Mixture of Lean Air and Fuel

You may not realize it, but the fuel that enters the engine also serves to cool the combustion chamber. If the air or fuel combination is excessively lean, the combustion chamber will not cool down as effectively, resulting in a lot of wasteful heat.

Because of the heat, the air-fuel mixture may self-ignite before the spark plug sends its spark, causing the engine to knock. These types of locations are dangerous for your engine’s internal components and can soon melt your pistons.

Wrong spark plugs

It is not typical for incorrect spark plugs to cause engine knock or detonation, but it does happen.

The ignition spark for the fuel-air mixture is provided by spark plugs. However, there are numerous varieties of spark plugs, and if you purchase the incorrect one, your engine may begin to knock.

The spark is too weak in the first case, and the spark plug may not produce any spark at all in the second. Check your repair manual for the correct spark plugs for your automobile model and make sure they’re placed correctly.

Can You Drive A Car With A Knocking Engine?

can you drive a car with a knocking engine

If the knocking isn’t too bad yet, doesn’t happen when the car is idle, and you only need to drive a short distance, you might choose to take the chance. It should run OK if you add some heavyweight gear oil to the crank. If only one of the cylinders is knocking, remove the plug from that cylinder to relieve strain on the rod. This should reduce the amount of knocking. Also, reduce the revs to 1500 rpm and drive as slowly as possible.

It is unsafe to drive with a rod knock and should be avoided. We advise that you have your engine inspected.

And, to avoid causing damage to the parts, especially the crank, fix the rod knock as soon as the banging appears. The problem will only get worse, and your engine will eventually be damaged. Your engine will eventually fail, and you’ll be saddled with a big repair expense.

Your car is making a knocking noise, and if you’re lucky and not far from home, you might be able to make it home or to a garage.

If the car is worth a few thousand dollars or more, you should park it right away unless you’re on a bridge or road with no one who can help you. Rescuers can assist you if you call for them.

A knocking engine, on the other hand, rarely lasts more than a few hours at best, and failure is inevitable if it develops a knock.

So, if it’s an old, cheap car, you might as well get it home if you can. It’s possible that the bill will be less if you make it halfway.

You can sometimes fix a knocking engine yourself if you are quite skilled and have a lot of tools. If you get to the problem soon, the parts could cost as low as a hundred dollars or less. 

If you drive it very far, you’ll tear the block, crankshaft, connecting rods, or all three, which means pulling the engine and spending money at an automotive machine shop, possibly more than it’s worth, or buying a new crankshaft, etc.

How Long Can Rod Knock Keep You Driving?

If you leave it alone, the rod knock will cause other issues such as wrist pin troubles, piston issues, cylinder wall issues, and so on. As a result, the length of time you can drive your car with a rod knock is determined by the general condition of the engine and other components.

Rod knocking occurs when the crankshaft journal, which connects the crank to the connecting rod of each cylinder, collides with the rod bearing, as previously stated. The rod in your car engine may shatter without notice once it starts knocking. This might happen the next time you get in your car. Alternatively, it could go on for months or even years.

However, if you don’t get the rod knock corrected, the engine will eventually give in and leave you stranded.

How to Repair a Knocking Engine

Now that you’ve learned about the various causes of engine knocking, you’re undoubtedly curious about how to remedy it.

The first thing you should consider is when the knocking began. If it happened after you refueled the car, the gasoline tank is most likely full of bad fuel. You may either replenish the fuel or use an octane booster to repair this.

A diagnostic scanner can also be used to look for any knock sensor-related fault codes. If you detect any issue codes relating to it, it’s time to replace the knock sensor or repair the wiring.

You should also inspect the spark plugs to ensure that you are using the correct spark plug type for your vehicle’s engine. To find the proper spark plugs, see your repair manual.

You should examine and modify the ignition timing if you have an older car or if the car engine has adjustable ignition timing. Check your service manual to see if your timing is adjustable or not.

If you are unfamiliar with altering the timing, have it done by a repair shop because the technique necessitates the use of some specialized instruments.

Frequent Asked Questions

Q: How Much Does It Cost to Fix Engine Knocking?

The cost of repairing an engine knock is not set in stone. Often, all that is required is the use of octane boosters or the replacement of the gasoline tank. In the worst-case scenario, the ignition timing will need to be adjusted or the knock sensor will need to be replaced. However, expect to pay between $100 and $200.

Q: Is engine knock caused by low oil?

Your car’s engine oil has nothing to do with the ignition timing or engine knocking. It may have an indirect effect, but if you have a low engine oil level, it may be the cause of the engine’s low oil pressure.

Q: Can the engine knock be fixed?

A knocking sound can be caused by a variety of factors, all of which can be harmful. The noise may be resolved by changing the oil and spark plugs, using a higher octane fuel, or cleaning the engine. However, if the noise continues, it’s time to go knock on your mechanic’s door.

Final Thoughts

If your car’s engine makes a knocking noise, it’s most likely a rod knock. We recommend that you don’t put it off any longer. With engine difficulties like this, the more you wait, the worse things get. Even if you try to do it yourself, we understand that it could be a pricey fix. However, dealing with it sooner rather than later, while you still have time, may save your engine. After all, getting your engine serviced is preferable to spending a lot of money on a new one.

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