Rod Bearing Replacement Cost – How Expensive Is It?

Have you noticed something knocking inside of your engine and you are looking to find out the rod bearing replacement cost? Well, if that is the case, then you are at the right place because this article will be all about this topic and we are going to elaborate on everything thoroughly.

• What Are Rod Bearings?
• What Rod Bearings Do?
• Rod Bearings vs Main Bearings
• Failure Causes
• Symptoms
• Diagnosis
• Replacement
• Replacement Cost
• Conclusion

Doing your own research before you go out there to visit a mechanic should be one of your top priorities. Especially if we are dealing with issues such as rod knock and problems with the main rod bearings. Why so?

Well, in some cases, a ton of mechanics will recommend you replace the whole engine. But this isn’t always the case because, in some situations, you can get away by only replacing the rod bearings on your car and call it a day. This is why you need to hurry into replacing the engine. Sometimes a simple rod bearing replacement will do the trick just fine. And we are here to help you out.

First, we are going to learn what are rod bearings in an engine. Then we will learn from what materials they are made and why they tend to fail notoriously on some BMW engines. Then we will cover the symptoms, the diagnosis, the replacement process, and also the replacement cost. So, if you want to learn more, follow along.

What Are Rod Bearings In An Engine

Now before we dive into more complex topics like the rod bearing replacement cost, let’s first cover what a rod bearing is in general. Since a lot of people confuse these bearings with wheel bearings and this is completely wrong. So, let’s elaborate more on this in-depth in the following chapter.

So, what are rod bearings? Well, rod bearings are also known as connecting rod bearings.

These bearings are split-sleeve bearings that are consisted of two equal semi-circular parts. And together when installed on the engine, they constitute a circle.

The rod bearings are seated carefully into their own housing. Usually, both the caps and the engine block have some indentations on them to allow the main bearing to slide in.

And once the rod bearing is seated on the connecting rod, you can install the piston. And once the piston is in the cylinder, you can place the crankshaft on top and then install the main caps and tighten everything up to spec.

Just beware that when doing this procedure, there is a lot of measurements that have to be done to make it all perfect, so we will not dive into details. We are only interested in the rod bearing replacement cost. But before we cover that, let’s take a look at what these bearings do.

What Do Rod Bearings Do

So, we learned more about the rod bearings and what type of components they are. We covered that they consist of two semi-circular parts that are installed between the crankshaft and the rod. But what is their purpose? Why you can’t just install the crankshaft without them?

Well, this is a good question that deserves an elaborate answer. Each piston has rod bearings and the purpose of these rod bearings is to make sure that the piston is at the right balance with the crankshaft and sits evenly all the time. That there is no play. Because if there is play, there will be a big imbalance inside the engine.

So, that is one thing. The other thing why your engine needs rod bearings is that these bearings keep your crankshaft lubricated.

On each bearing, there is enough clearance that allows oil to sip in. Just enough oil, to create a layer between the rod bearing and the crankshaft of the engine.

And this layer of oil basically prevents engine wear. It keeps the rod bearings nice and lubricated all the time.

And when there is no oil or there is dirty oil, this will reflect on the life of the bearings. In this case, the bearings will start to wear and you will have to replace them with new ones or trash the whole engine. But what is the rod bearing replacement cost? More on this we are going to cover more in a bit.

Rod Bearings VS Main Bearings

What is interesting to note before we cover the rod bearing replacement cost is the rod bearings vs main bearings. There are a lot of people who confuse these two types of bearings and this shouldn’t be the case. Why so?

Well, technically they are both bearings. But they have different tasks to fulfill. The job of the rod bearings is to make sure that the pistons are balanced. While the purpose of the main bearings is to make sure that the crankshaft of the car is perfectly balanced.

So, to sum things up, rod bearings are dedicated for the piston rods. While the main bearings are only there to make sure that the crankshaft sits nice and tight to the bottom of the engine.

What Are Rod Bearings Made Of

Now as we covered what are rod bearings and what are their task inside the engine. We can now move on and cover another topic before we dive into the rod bearing replacement cost. And that is the material from which the rod bearings are made of.

These bearings are often made out of nonferrous metals. These are the metals that do not contain iron. Namely, bronze, babbitt, or aluminum. These are rather soft metals. Especially bronze is an alloy composed of brass and zinc.

The rod bearings can be single metal. Namely, aluminum or copper bearings. But they can also be bi-metal or tri-metal.

The tri-metal are probably the most common ones. These bearings are composed of steel back, copper or aluminum alloy, a nickel barrier, and an overlay. This overlay is often a thin tin flash that is applied on the overall surface of the bearing. But what is the rod bearing replacement cost? More on that in a bit.

What Causes Rod Bearing Failure

Now as we covered the rod bearing and we learned from what materials is this bearing made of. We can slowly move on and start learning about the common causes of failures of these bearings.

As you probably know, rod bearings tend to wear and when they wear out, they will start to create a ton of problems inside the engine. So, what causes them to wear out? Let’s elaborate more on this in the following chapters.

1. Low-Quality Bearings

The first cause for rod bearing failure and the need to learn the rod bearing replacement cost is the low-quality bearings.

Some engines are quite susceptible to rod bearing failures. Not all but there are some engines that go through these bearings much sooner than expected.

Especially on high-performance BMW engines. Namely, the S62, S54, S65, and S85 are all susceptible to problems with rod bearings. So, whenever you plan to purchase an M5 or an M3 with one of these engines, you should definitely look if the rod bearings were replaced once in the past.

Because if they weren’t, a proper inspection of the engine has to be done to determine if there was any damage done to the crankshaft. Now let’s move on to the next causes before we cover the rod bearing replacement cost.

2. Low Oil Level – Rod Bearing Replacement Cost

The next cause for rod bearing failure that is rather common is the low oil level. Low oil level can basically ruin any type of bearing, it doesn’t matter if we are talking about main bearings or rod bearings.

When there is a lack of lubrication, there will be problems with increased wear inside the engine. Mainly because not only that oil lubricates the bearings, but it also dissipates heat.

So, if you don’t have oil flowing in the crankshaft and the bearings are left bone dry, they will start to create friction between them and the crankshaft and there will be a ton of wear both on the bearings, as well as on the crankshaft.

So, this is why you need always to monitor the oil level and make sure that you have enough oil inside of the engine in order to avoid any of these situations because the rod bearing replacement cost can be rather expensive to do. Now let’s move on to the next probable cause.

3. Rare Oil Changes

And the last probable cause for rod bearing failure and paying the rod bearing replacement cost is the less frequent oil changes.

Poor maintenance is often the biggest problem for bearings. There are people who change the oil on 20,000 miles. Even though they are supposed to do this on 10,000 miles or less.

So, in these situations what happens is that the bearings will start to wear quite exponentially, much faster than normal.

Mainly because the engine oil is not doing its job which is lubrication. There are deposits inside the engine oil that should be removed when the oil is flushed. And when the burnt-out oil and these deposits come into contact with the bearings, they will basically annihilate them.

So, even after one delayed oil change, you can suffer from rod bearing failure. Especially on engines that are far more sensitive to these issues with rod bearings.

This is why you should do your oil changes every 8,000 miles if you want to get the maximum from an engine and never worry about it failing and you paying the rod bearing replacement cost. But what are the rod bearing failure symptoms? Let’s elaborate more on this in the following chapters.

Bad Rod Bearing Failure Symptoms

So, we have covered the causes of rod bearing failure. Now we think that it is time to cover more on the symptoms that rod bearings produce.

It is worth noting that there are not a lot of these symptoms present. But when they happen, you just know that there is something wrong with the engine. This is why we are going to elaborate on them in detail and learn more about what you can expect a rod bearing failure to be like before we discuss the rod bearing replacement cost.

1. Rod Knock

The first and most common symptom that you will notice when you have bad rod bearings is the rod knock. But what is a rod knock?

Well, this is an audible symptom that indicates that you have a problem with your vehicle. Namely, the engine. The rod bearings are worn out.

And once the rod bearings wear out, the tolerances between the rod and the crankshaft increase. And this big gap creates a very strong audible noise known as knocking.

So, when a rod starts to knock, it is rather obvious and you can diagnose it rather easily. Later on, we are going to elaborate more on the sound and learn how we can diagnose rod knock. Now let’s continue with the symptoms before we cover the rod bearing replacement cost.

2. Drop In Oil Pressure

The next symptom in our list that is concerned with bad rod bearings and basically tells us that we need to learn the rod bearing replacement cost is the drop in oil pressure. So, what does the oil pressure has to do with the rod bearings?

Well, it has a lot to do with. Mainly because when you have a rod knock, it means that the oil flows easier than it should. This means that there is not enough pressure inside the engine.

And low oil pressure basically is a clear indicator of a worn-out engine with bad piston rings and bad rod bearings.

When you want to buy a car and you don’t see normal oil pressure, just stay away from it. Especially low oil pressure which is 99% of the time indicating that you are dealing with an engine that is due to be rebuilt or completely replaced. But what is the number that indicates low oil pressure?

Well, anything below 20 PSI is a sign that you have a worn-out engine that has bad bearings or piston rings. In this case, rod bearing replacement cost is essential. But more on that in a bit.

3. Copper Or Aluminum Shavings In Oil

The next symptom on our list that indicates a need for rod bearing replacement is the copper or aluminum shavings in the engine oil.

This can be checked if you remove the dipstick and see if there are some metal particles on the tip. Yellow shavings often indicate rod bearing wear because copper or bronze has that same coloring.

Aluminum bearings can also wear and create shavings in silver color. So, checking the oil regularly is one way to prevent a lot of these things. Especially a complete engine failure and rod knock and paying for rod bearing replacement cost. But more on that in a bit, let’s now learn how to diagnose bad rod bearings.

Rod Bearing Diagnosis – Replacement Cost?

Now let’s learn more about the rod bearing diagnosis before we cover the rod bearing replacement cost. So, how is this problem diagnosed?

Well, the knock is one sign. But you definitely want to catch the problem earlier than this. So, if you have a drop in oil pressure, or possibly some metal shavings in the dipstick it is a good thing to react before the problems become bigger.

But the real diagnosis can be done if you remove the oil pan and remove the rod caps. There you will be able to inspect the bearings one by one and see if they have any wear on them.

A worn bearing is usually identifiable because it has a wear pattern. Also, there should be some grooves on the crankshaft as well and the crankshaft would be in need of resurfacing as well.

This is why the earlier you diagnose the problem. The cheaper the repair would be and the lower the rod bearing replacement cost will be. But how are rod bearings replaced? Let’s find out more about that next.

Rod Bearing Replacement – Cost?

Another topic that we would like to cover before we cover the rod bearing replacement cost is the replacement itself. How this procedure is done? Do you have to remove the engine?

Luckily in most cars, these bearings can be replaced by only lifting the car in the air and doing the bearings one by one.

This is a rather tedious process though. But it is a better approach than removing the whole engine apart. Mainly because it saves a lot of time on labor that you don’t want to spend. The crankshaft can also be dropped and polished if there is any need to do so.

But what is the rod bearing replacement cost? How much can you expect to pay to get this all sorted out? Let’s find out more about that next.

Rod Bearing Replacement Cost

Now let’s take a look at the rod bearing replacement cost. How much money you will have to pay for this job?

Well, this is an expensive job. Mainly because of the labor. The bearings will not cost you more than $250. But the labor can cost anywhere between $1,000 to $2,000, depending much on the engine that we are talking about.

Also, if the crankshaft needs to be polished, you will have to pay extra for machining. And this can also be in the range of $500 to $1,000. Overall, rather an expensive job. This is why you need to do your oil changes regularly in order to avoid paying such an expensive cost to replace these components.

Can I Continue Driving With Bad Rod Bearings?

Well, driving like this is possible, you can drive the car. But the car will eventually fail and the engine will have to be completely replaced.

Mainly because if this problem isn’t detected and sorted on time, it will create a lot of damage inside the engine and the damage will be irreversible. This is why we recommend replacing these components before things get worse.

Conclusion To Rod Bearing Replacement Cost

In this article, we have covered quite a lot when it comes to rod bearings. First, we learned what rod bearings are and what they do. What is their function precisely, as well as from what metals are they made out of.

Then we covered the common causes of bad rod bearings, as well as the symptoms that these bearings produce when they fail. We also learned the diagnostics process, as well as the replacement, and the rod bearing replacement cost that has to be paid in order to get your engine back to proper working condition.