Rod Bearing [All you need to know]

The connecting rod bearing is one of the least known engine components in your vehicle. If you have a connecting rod bearing problem, you must fix or replace it immediately or your engine will not start. This page explains what a connecting rod bearing is, how to replace it and how much it costs.

The connecting rod bearing in a conventional automobile engine is just a sliding bearing. It is not the same as a ball bearing with balls. The connecting rod bearing holds the rotating shaft in place. During the combustion cycle, this bearing keeps the connecting rod straight. Connecting rod bearings are sometimes referred to as rod bearings.

The cost of replacing connecting rod bearings ranges from $2,000 to $3,000. Parts and labor are already included in this price. Connecting rod bearing repair usually involves cleaning the engine and cooler ducts, as well as replacing gaskets, seals and cylinder head bolts.

Read on to find out more about connecting rod bearings, what causes connecting rod bearing difficulties, how to fix these difficulties, and how much it costs to repair or replace them.

What Is a Rod Bearing?

A connecting rod bearing is a sliding bearing in automotive technology, not a ball bearing with balls. The connecting rod bearing supports and holds the rotating shaft in the supported section.

This is done to maintain the straightness of the connecting rod during the entire combustion cycle. As it is directly coupled to the connecting rod, the term can also be applied to the connecting rod bearing. These are engine parts, just some of the many components or elements of the engine. These components are housed in the engine block of the car.

If the technician thinks your car engine’s connecting rod bearings need to be replaced, you could be looking at spending $2,000 to $3,000 on components and labor. This service usually includes cleaning the engine cooler ducts and replacing seals, gaskets, cylinder head bolts, and connecting rod bearings.

However, before taking the car to the mechanic, you should first determine if your connecting rod bearing is indeed fractured or worn.

What Happens When Rod Bearings Go Bad?

When the connecting rod bearings wear, the clearance between them and the supporting connecting rod becomes too large. As a result, the large end of the connecting rod will collide with the moving crankshaft. The sound of the piston hitting the engine is then heard. Consequently, these knocking noises are the main indications of engine bearing deterioration.

In many circumstances, an engine with a defective connecting rod bearing can cause the “check engine oil” light on the dashboard to come on. Depending on the severity of the bearing problem, this light may or may not go out after the engine has been running for a few minutes.

Spun Rod Bearing

One of the most serious problems you must address if you want to avoid connecting rod bearing failure at all costs is what automotive technicians refer to as “spinning rod bearings”.

When a connecting rod bearing spins, it indicates that the connecting rod bearing lubrication system has failed. This implies that the connecting rod bearing is not lubricated when the shaft moves continuously in this dry bearing.

The shaft soon becomes very hot and swollen. The shaft grabs the connecting rod bearing and pulls it out of the pin when it enlarges. At this point, the connecting rod bearing has been welded to the rod and now rotates along with it.

If you continue to drive the car with the rod turning for many miles, the rod bearing will become very hot. This will cause the rod to fall out. The engine of your car will then be irreparably damaged.

Are There Several Connecting Rod Bearings?

The ball joint is characterized by two spherical metal bands, one at the top and one at the bottom. When completed, they are only two smooth, circular metal bands. The upper and lower metal bands are semi-circular.

The upper section of the driveshaft bearing, for example, is placed on the car chassis. The lower section of the driveshaft is attached to the upper section once mounted.

In the upper section, there is a through-hole. The hole allows lubrication to enter the inside of the device. As a result, the drive shaft can rotate in the rod bearing without overheating.

There is only one general design for the rod bearing. However, it can also be called by other names, such as connecting rod bearing, connecting rod end bearing, Heim seal (USA), and rose seal (UK). The fundamental design may vary, but the essential form and function are usually the same.

The piston rod is connected to the bearing journal by means of these bearings. The bearing journal is where the piston rod contacts the driveshaft and rotates it. Replacing connecting rod bearings is a common engine repair or rebuilding process.

The engine connecting rod bearing is different from the main bearing. The torque parameters for the connecting rod bearing and main bearing are different. The main bearing is located between the crankshaft and the engine block, while the connecting rod bearing is located between the connecting rod and the crankshaft.

Therefore, the word “connecting rod bearing” is a contraction of “connecting rod bearing”. The movement of the crankshaft pin on the connecting rod is provided by the connecting rod bearing. The cyclic stress received by the piston is transmitted through this revolution. The connecting rod bearing is located at the large end of the connecting rod.

Why Identify connecting rod bearing problems?

If connecting rod bearing failures are not identified and repaired, the engine can fail catastrophically. Therefore, manufacturers have modified their engine design by producing sealed gearboxes.

When submerged in transmission fluid, the modern engine design allows the driveshaft to rotate. As a result, connecting rod bearing problems are quite unusual in today’s automobiles. On the other hand, in sealed gearbox designs, a reservoir for transmission fluid is no longer necessary.

Because it is the first engine component that generates early warning signals of transmission oil loss, this reservoir is very useful. As a result, if you hear a persistent ticking sound inside the engine that becomes louder when rotating at high speeds, you should suspect a bearing problem.

Worn Out Rod Bearings

If you hear the dipstick knocking in the engine, the dipstick bearing may be worn or the oil pressure may be too low. This noise can be silenced by changing the oil filter and adding new engine oil. However, even after changing the oil, you have noticed that the noise is still there, and your rod bearing may have been damaged and can no longer be repaired.

If you hear the knocking of the connecting rod bearings, you only have 30 seconds to completely freeze the engine. When the oil film is unable to lubricate and hold the connecting rod on the crankshaft, contact between the crankshaft and connecting rod occurs. At the current engine speed, the connecting rod bearing can only survive this time.

Spun Rod Bearing

Another problem to avoid is spinning connecting rod bearings. This occurs when the connecting rod bearing becomes entangled in the crankshaft journal. The bearing will tear the large end bore of the connecting rod.

They have the potential to damage the shaft journal. Sometimes they can break the connecting rod. The engine, on the other hand, can survive longer if the bearing rotates. It has a range of about 50 miles.

Symptoms Of A Bad Rod Bearing

You should recognize the signs of connecting rod bearing problems as soon as possible. This will help you avoid any circumstances that may cause irreparable damage to your automobile engine.

Here are a few things to look out for.

  • Loss of oil pressure
  • Silver flaking oil
  • Engine rumbling
  • Oil with a coppery sheen
  • Transmission noise and belt wear

Causes Of Rod Bearing Failure

The problem of connecting rod bearings has not appeared all of a sudden. There are many reasons for them, and you should understand the common causes in order to avoid them:

1. Abrasive contaminants.

Connecting rod bearings can be damaged by various contaminants present in the lubricant. If these abrasive contaminants are not completely removed from the engine during overhaul, these contaminants are often introduced into the connecting rod-bearing lubrication system.

These contaminants can come from deformed connecting rod bearing bores or worn crankshafts. They can cause uneven wear of the connecting rod bearings at the connecting rod contact points.

2. The different parts collide

When the crankshaft journal collides with the bearing, the engine makes a knocking sound. Ignoring these knocking noises will simply aggravate the situation. As a result, the engine will suffer further damage.

3. Spinning bearing

The connecting rod bearing sticks when the bearing rotates. The distance between the inner surface of the bearing and the connecting rod widens as a result. As a result, excessive clearance forms between the two connecting rod components, causing a knocking sound.

Slewing bearings are also used for the following reasons:

  • Loss of lubrication
  • Overheating
  • Deficiency of lubrication
  • Contamination of the lubricating fluid
  • Excessive operating load

How To Replace Rod Bearings

The connecting rod bearing is a critical component of every engine, whether it is a Toyota or a Ferrari. The connecting rod bearing ensures that one end of the connecting rod moves smoothly around the crankshaft while the other end surrounds the piston pin. Engine bearing replacement is a typical operation for every engine replacement.

1. Remove the piston

Remove the piston and connecting rods from the crankshaft. The “big end” of the connecting rod (the larger one) is attached to the crankshaft by two screws securing the end caps. The “small end” is secured with a wrist point. Two snap rings to secure the piston pin to the piston. Remove these clips and slide the piston pin out of the piston and rod ends. This should cause the lever to release.

2. Remove the old bearing.

You can carefully pry out the old bearing using a screwdriver and hammer. Tap the edge of the bearing where it meets the end cap and vice versa. Do not attempt to pull the bearing out from the side.

3. Clean bearing surface

Thoroughly examine the bearing surface for dirt and debris, as this can cause bearing failure and limit the life of the motor. Also, prior to installation, clean the bearings.

4. Assemble

Insert one bearing into the larger end of the connecting rod and the other into the end cap. The end cap and rod end create a circle around the crankshaft when all parts are connected. The bearing has a small notch at both ends.

These notches must be opposite each other, not on the same side when the rod and end cap are assembled. This is essential to maintain optimum oil pressure. Repeat the operation with the rest of the dipsticks. Check that the bearing fits snugly on the connecting rod and that there is no play.

5. Install the New Rod Bearing

Once all the disassembled parts are clean, start reassembling them in the reverse order in which they were disassembled. Apply a coat of engine oil to the new connecting rod bearing before installing it.

Rod Bearing Replacement Cost

Many people may not be qualified for the task of replacing Robb bearings. If you are unsure about doing it yourself, you can always hire a professional vehicle maintenance shop to handle it. In this situation, the cost of a replacement should be between $2,000 and $3,000. This includes both components and labor.

If your engine is significantly damaged due to connecting rod bearing difficulties, and you need new pistons and connecting rods, as well as new timing chains, camshaft bearings, and crankshafts, you should purchase a new engine assembly.

However, if the broken connecting rod bearings are the only problem and the crankshaft and other engine components are not damaged, you should simply replace them.

Final Thoughts

The connecting rod bearing in a conventional automobile engine is a sliding bearing that is used to fix the rotating shaft where it should rest. It is not the same as a ball bearing. The bearing keeps the connecting rod straight throughout the combustion cycle by supporting the rotating shaft. The word “connecting rod bearing” can also be used to refer to the “connecting rod bearing”.

The average cost of replacing a connecting rod bearing is between $2,000 and $3,000. Parts and labor are already included in this price. Repairing the connecting rod bearings will require flushing the engine and cooler ducts, as well as replacing gaskets, seals and cylinder head bolts.

What exactly is a rotating connecting rod bearing? The connecting rod bearing is welded to the crankshaft and rotates inside its housing. This means that there is a shortage of oil and a lot of metal debris floating in the oil system.


Hi, I'm the initiator and writer of this blog. Cars were and will be my first love, and my favorite hobby, that's why I decided to start this blog and write about my discoveries and techniques to improve my cars or repair them.