How To Extend Life Of An Engine With Rod Knock

Engine troubles and maintenance are something that most people do not want to go through. When a driver’s vehicle engine malfunctions, they consider trading it in or selling it because they believe it will be an expensive fix. Fortunately, some engine problems are easier to resolve than others.

One of these engine difficulties that may cause you to consider trading or selling your vehicle is engine knocking. In our guide, you can learn more about mechanical problems and faulty parts leading to engine knocking.

By the end, you’ll see how to stop engine rod knocking depending on the cause of the problem.


You could find simple solutions for a rod knock fix, or the knocking problem is too much, and you need to get rid of your vehicle before significant engine damage occurs. (Read What Size Socket For Lug Nuts)

How Long Does An Engine Last With Rod Knock?

An engine makes many noises, yet knocking noises are among the worst as the faster you go, the more pronounced they are.

The noise or sound of one or more connecting rods hitting or rubbing against the crankshaft as it revolves in the cylinder bores is called rod knock.

The pistons and crankshaft are joined by connecting rods. You’ll find a bearing between the conrod and crankshaft. It is made of a softer metal than the crankshaft and the con rod.

By default, car engines are built with a clearance tolerance for the bushing to fit in the crankcase journal. The little clearance allows engine oil to flow over the metal surface, reducing premature wear.

The metal bushing between the con rod and the crank will wear out with time, resulting in rod knock.

The bushing takes hundreds of thousands of miles to wear, so malfunctions occur because of regular wear over the engine life.

Rod knocks are most commonly caused by premature wear, and you could wonder what is causing premature wear? There are common issues that result from poor vehicle maintenance. Dirty motor oil, low oil level, low oil pressure, and engine overheating are common causes.

It is best to get on top of the issue before replacing the entire engine.

spun bearing

Spun Bearing

Spun bearings result from poor cylinder wall circumstances. Spun bearing occurs when an engine lacks lubrication, and the crankshaft rotates with the bearing instead of inside it.

This is commonly caused by stretching connecting rods or bolts during an engine overhaul. Lack of lubrication, severe heat and high operating loads can also cause bearing wear.

In most cases, it is best to stop the engine immediately until you get the problem fixed, or you could face an entire engine rebuild if you carry on driving with these damaged rods. (Read What Size Is A Spark Plug Socket)

Rod Knock Symptoms

There are a few indications to look for with rod knocks, just like with any other system component in your car.

These symptoms are as follows;

Knocking sounds: The knocking sound is the most prevalent sign of rod knock. When you turn on your automobile with a rod knock installed, you will hear a slamming or knocking sound. The noise level will rise as you press down on the gas pedal.

Low oil pressure: As engine components such as the crankshaft, camshaft, and bearings wear down, the oil pressure in the engine drops. This is more obvious when the car is first started.

It may cause the check engine light and the oil light to illuminate on your instrument cluster, suggesting a problem with the oil pressure.

If the lights go out after a few minutes of idling and the car’s engine warms, and the pressure returns, it means you have a knocking engine.

What Causes Knocking Rod

Wear or damage to the engine’s internal parts is the most common source of rod knocks. So what could have caused the engine’s internal parts to wear out? An irregular oil change and a low oil level are the most common causes.

The density, viscosity rating, and lubricating characteristics of motor oil deteriorate with time as it travels through the engine. These factors contribute to the production of engine sludge and internal corrosion.

Low oil pressure and poor circulation will follow if you drive your car with a low oil level.

Excessive engine wear and damage could develop because of this. A variety of mechanical issues can cause rod knocking. These are some of them:

  • Broken/ loose timing chain tensioner
  • Worn main bearings
  • Worn water pump
  • Worn alternator rotor bearings.

engine to be save

Can You Save An Engine With Rod Knock?

One thing that can help in such a scenario is to keep your engine cool, yet this won’t give you a long life of operation. At best, it will limit engine rod knock.

Here are some of the things for how to fix rod knock. However, some offer a rod knock quick fix rather than fixing your engine properly.

Replace Worn Bearings

Bearings greatly influence the motion of the piston and crankshaft. As a result, when crankshaft bearings fail, they will create noise and knock.

When rod knock occurs, it’s recommended to start with a bearing inspection. Replace your bearings right away if they’re worn out.

Replace Damaged Connector Rods

With engine knocking, it’s possible that damaged connecting rods are to blame.

If you replace the faulty parts, the knocking noises will stop. Replacing connector rods is far less expensive than replacing the whole engine.

Replace Piston?

The engine knock could be faulty piston components or the whole piston. So, if you hear knocking sounds, check the piston function.

Replace Faulty Spark Plugs

Spark plugs control the actions of the connector rods and pistons through the igniting of the fuel. If you have faulty plugs, these won’t work as they are supposed to and can lead to a knocking noise.

It is straightforward to replace faulty spark plugs so long as you have the right-sized plug socket. If knocking occurs after changing plugs, it signifies the problem is elsewhere.

Avoid Overloading Your Car

Every vehicle has a maximum weight capacity. As a result, if your car’s engine is overloaded, it won’t respond. In addition, some parts, such as loose or slightly damaged pistons and a defective timing belt tensioner, may be harmed if this condition persists.

It is recommended that you avoid overloading, even if your vehicle appears to cope—a Subaru Forester, as an example, can carry a lot. Yet, the cost of an engine fix can run into the thousands. (Read Socket Conversion Chart)

Use Better Quality Oil

Failing to use lubricating oil regularly or using low-quality lubricating oil can cause dehydrated pistons, damaged bearings, and knocking noises.

As a result, for the pistons to move more smoothly, use high-quality lubricating oil. Engine oil that is too thin or substandard could easily be the real answer you have knocking. In addition, you’ll see the effects on your plugs as they may be coated black from burned engine oil.

Check Coolant Level

Engine overheating has the same effect as cheap oil and causes a knocking noise. As the substance in air conditioners, coolant is essential to prevent engine overheating and thus stop your car oil thinning too much.

Can Thicker Oil Stop Engine Knocking?

Here are practical steps on how to diagnose and fix rod knock.

Examine your oil condition and the amount of oil in the engine.

  1. Remove your oil dipstick.
  2. Clean it with a rag.
  3. Examine the color. You have dirty or burned engine oil if it is dark.
  4. Re-inspect the dipstick by reinstalling it and pulling it out.

Engine knocking will be caused by dirty engine oil, which leads to excessive wear and damage.

How to fix rod knock

A rod knock shows a problem with the engine’s inner components. Rod knock can be caused by various circumstances; some require costly repairs, while others do not. However, this does not imply that your engine is beyond repair.

There are a few actions you may take before visiting a mechanic to lessen rod knock and possibly stabilize your engine before undergoing a comprehensive repair.

Here’s how to deal with knocking before you consult the experts. Do these regularly, and you can extend the life of an engine without needing repair.

Do An Oil Change

Place a catch pan right under the drainage plug. Get a big socket and a wrench. Locate the crankcase drain plug and loosen it to drain the oil.

Reinstall the draining plug after draining all the oil.

Make sure you follow the manufacturer’s specs.

Remove the oil filter by twisting it clockwise with an oil filter wrench. Install a new filter and torque to specs. Replace the engine oil with the same viscosity or a better-quality oil designed to help knocking.

If you don’t know how many quarts your engine needs, keep checking the oil. 4-5 quarts for a four-cylinder engine

Check Your Con Rod Bearing

A loose connecting rod cap causes a knocking noise. Inspect the bolts holding your con rod to the lid and use a torque wrench to tighten them.

Use a Fuel-injection Cleaner

When you replenish your gas tank at the gas station, grime and filth may get into your tank. The gasoline pump transports dirt and grime, creating engine knocking.

Cleaning your fuel injection system will remove filth and ease the rod knock problem. Take note not to pour fuel injection cleaner on older carbureted automobiles.

How To Extend Life Of An Engine With Rod Knock (1)

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