Will rod knock cause check engine light

Will Rod Knock Cause Check Engine Light? A Step by Step Guide For 2023

Engine problems are the most annoying thing that a motorist faces quite often. A motorist may often hear a noise of hammering coming out of his automobile while he is driving it. This may be because of rod knock.

Rod knock causes a lot of problems. One common question about rod knock is “Will rod knock cause check engine light?”. To answer your various relevant questions, we designed this article in a way that will provide you every possible information that you may require about rod knock.

If you are a motorist and you face such problems while driving your automobile, this article is for you. So read the whole article to know about rod knock and get your answers.

What is rod knock?

What is rod knock

Rod knock is the noise that is produced when one or more connecting rods strike or rub against the crankshaft, as the crankshaft revolves in the cylinder bores. Rod knock may also be caused by a number of other factors.

Pistons and the crankshaft are linked to connecting rods in an internal combustion engine. In addition, there is a bushing, which is more often known as a bearing that is formed of a softer metal than the crankshaft and the connecting rod. This bushing is located in between the crankshaft and connecting-rod.

The clearance tolerance that allows the bushing to fit in the crankcase journal is often built into automobile engines during the manufacturing process. Because of the narrow clearance, the engine oil may flow freely over the metal surface, which helps to avoid early wear and tear.

Rod knock, on the other hand, is the consequence of the metal bushing that is located between the connecting rod and the crank starting to wear away over time.

Rod knocks are not normally caused by regular wear since it takes thousands of miles for the bushings to wear out. Premature wear is the most common cause of rod knocks. There are a variety of factors that might contribute to premature wear, such as filthy motor oil, low oil level, low oil pressure, and excessive engine heat.

What is Spun bearing?

What is Spun bearing

Now you may ask what a spun bearing is. Well, a spun bearing is the result of unfavorable conditions occurring in the cylinder bores of an engine. A spun bearing is what happens when the engine lacks lubrication and the crankshaft revolves with the bearing rather than within the bearing.

In most cases, this is the result of connecting rods or nuts being stretched out as a result of poor bolt torture during the process of engine rebuilding. The bearing may also get worn due to a number of other circumstances, including an absence of lubrication, an excessive amount of heat, and high operating loads.

Signs of rod knocking

Signs of rod knocking

There are a few signs that might inform you when you have a rod knock. The following is a list of these symptoms:

  1. Sounds like knocking are one of the most typical indications that a rod has been knocked. When you switch on your automobile, you will hear a sound that is quite similar to someone pounding metal on your iron door. This sound will be a hammering or knocking sound. As you press more on the gas pedal, the volume of the noise will rise.
  2. Reduced oil pressure is the result of components inside the engine, such as the crankshaft, camshaft, and bearings, wearing down over time. When you initially start up the vehicle, you will sense this more than at any other time.

Cause of rod knock?

Cause of rod knock

In most cases, there is only one issue that may generate rod knocks, and that is damage or wear to the internal components of the engine. Generally, it is brought on by infrequent oil changes and inadequate levels of oil in the vehicle.

As time passes in an engine, the motor oil gradually loses its density, as well as its viscosity rating and its ability to lubricate moving parts. All of these factors contribute to the creation of engine sludge as well as internal corrosion.

If you continue to drive your vehicle with a low oil level, the pressure in the oil will decrease, and it will not circulate as effectively as it should. Because of this, the engine could suffer from excessive wear and damage.

Rod knocking might also be caused by a number of other mechanical issues. These are the following:

  • A timing chain tensioner that is either broken or loose.
  • The main bearing was completely worn out.
  • Water pump bearing that is worn out
  • A flex-plate or flywheel that is cracked or fractured.
  • Rotor bearings on the alternator was worn out.

Let’s know whether rod knock cause check engine light?

Let’s know whether rod knock cause check engine light

A spun bearing is the root of the problem known as rod knock. You will not see the check engine light come on as a result of this, but you will hear it whenever your engine is running. It is really noisy, and it seems like someone is pounding away at the block with a hammer.

In some circumstances, it will cause the “check engine” light as well as the “oil” light to illuminate on your instrument cluster, suggesting that there is a problem with the oil pressure. A rod knock is indicated if these lights turn out after a few minutes of driving with the engine running or idling, and then the pressure returns to normal.

FAQ (Frequently Asked Questions)


These are some common questions people have about rod knock:

1. Why does my car’s engine make that knocking sound when it’s cold?

The occurrence of piston slap is one of the most typical reasons for engine noise during the cold start. When the cylinder wall and the piston of an old engine no longer have the precise tolerances of a new engine, a phenomenon known as piston slap may occur.

2. How long can an engine keep running if it has rod knock?

As soon as an engine begins to bang, the rod might break without any prior notice. It may be the following time you start it in your drive, or it may continue running for the next half a year. However, at some point in time, the engine will fail, and you will find yourself in an unfamiliar location.

3. What are the consequences of not repairing the rod knock?

Rod banging is an issue that may occur with the moving elements of the internal engine. You’ll know it’s happened because your vehicle will start making knocking or banging noises, your oil pressure will be low, and the “check engine” light will come on in your instrument cluster.

If you are unable to locate the source of the problem and correct it in a timely manner, the engine will suffer severe damage as a consequence.

4. When the engine becomes warmer, does the rod knock go away?

As the engine warms up, a rod knock will become more audible and noticeable. It is not something that will go away when the engine heats up. In the event that it occurs, the problem is usually something like an exhaust leak that automatically seals itself as the engine manifolds grow warmer.

5. Is vibration caused by the rod knocking?

Knocking sounds from the rods are most audible while traveling at faster speeds (over 2500 RPM). Therefore, lightly touching the gas pedal might cause an unique back rattle that occurs between 2500 and 3500 revolutions per minute. It is possible for it to even double knock if significant rod bearing metal has been broken away. As a direct consequence of this, the piston will collide with the cylinder head.

6. Will using heavier oil prevent the rods from knocking?

A rod knock is a sound that might be indicative of wear or damage to your engine’s components, as was discussed before. Therefore, switching to an oil that has a greater viscosity rating (also known as thicker or heavier oil) can assist in eliminating or, at the very least, reducing the rod knock.

Moreover, it will enhance the life-cycle of your engine. This does not excuse you from determining and addressing the root source of the knocking, though.

7. Is it worthwhile to repair the rod knock?

The issue of a rod is not one that will resolve itself on its own. You need to diagnose and find a solution to the issue as soon as possible, before it becomes worse. If you take the time to identify and correct the rod knock-on time, it won’t put a significant dent in your finances. Therefore, it is in one’s best interest to fix a rod knock at an early stage.

Final Word

People have so many questions about rod knock, as it is a concern for them. In this article, we tried to sort out whether rod knock cause check engine light and the very basic cause of this, along with other relevant frequently asked questions.

We hope, after reading the whole article, you got all your answers to the relevant questions regarding rod knock.

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