BMWs, M3s in particular, are famous for rod bearing issues. If you suspect that the rod bearings in your vehicle are reaching the end of their lifespan, it may be time to replace them before the issue gets worse. But, how much will this cost?

Depending on where you go, replacing your M3’s rod bearings could cost anywhere from $1,800 to almost $10,000. However, the average cost is just about $2,500-$3,500.

Independent shops will almost always be less expensive than the dealership, which may give you an estimate as high as $9,500. 

Below, we’ll discuss everything you need to know about replacing your M3’s rod bearings. Keep reading before you accept a mechanic’s estimate!

How Much Does It Cost to Replace M3 Rod Bearings?

The price you’ll pay to have a mechanic replace your rod bearings can vary significantly based on the shop you visit. BMW dealerships are notoriously expensive, and some independent mechanics do not have the knowledge or tools to work on these complex cars.

If you want to visit an independent mechanic for this job, make sure to find one that knows how to work on BMWs. While a dealership will likely quote you anywhere from $5,000-$9,500 for the job, an independent mechanic will usually do it for between $2,000-$3,500. 

How Much Does It Cost to Have a Professional Replace Your Rod Bearings?

Replacing a vehicle’s rod bearings is no easy feat. It takes an average of 12 hours to complete the process, but the total time could range between 8-15 hours. 

When you visit a mechanic, you’ll have to take labor costs into account when thinking about the final price. The labor rates at a BMW dealership are typically higher than those at an independent shop, which contributes to the cost difference. 

Rod bearings themselves are not particularly expensive. Depending on the parts your mechanic uses, you could be looking at anywhere from $175-$650 for the new bearings.

However, most mechanics will do more than just replace the rod bearings when they perform this work. The rod bearings are not easy to access, so it’s best to ensure nothing else will go wrong in the future. For this reason, your mechanic may suggest the following additional work:

• New seals
• New gaskets
• New cylinder head
• Engine and cooler line flush and replacement

For this reason, the parts often add an extra $900-$1,500 to your total cost. In the end, your total cost could get up to $5,000, and that’s not even including any additional fees!

Although these estimates do not seem too high, there are often additional fees to consider. BMW is more likely to charge higher fees than an independent shop, which is where some of their incredibly high estimates come from. 

How Much Does It Cost to Replace Your Own M3 Rod Bearings?

Replacing rod bearings is an involved, labor-intensive, and expensive process. It requires a lot of time, effort, and disassembly to do correctly. You should only attempt to replace your own rod bearings if you’re 100% of what you’re doing.

If you decide to replace the rod bearings yourself, you can cut out all the labor costs. Since the process takes such a long time, this can end up saving you more than half the mechanic’s estimate!

If you just want to replace the rod bearings, expect to pay between $175-$650 for them. There are many types of rod bearings available online, and the higher-quality they are, the more expensive they’ll be. 

Rod Bearing Kits

If you want to do the additional work mechanics often recommend, consider purchasing a rod bearing kit. These kits have everything you need to completely overhaul your rod bearings, including:

• Rod bearings
• Connecting rod bolts
• Hardware and gasket set

For an additional cost, you can opt for extra pieces like:

• Motor mounts
• Engine oil and filters
• Steering tie rod boots
• Front subframe hardware

In general, these kits cost between $750-$1,500. Adding the extra pieces will add approximately $350 to the total price.

Remember, you should only attempt to replace your own rod bearings if you have extensive mechanic experience. This is a very complicated task, and getting something wrong could cause additional damage. 

What Are Rod Bearings?

If you aren’t too familiar with M3 mechanics, you might be wondering what exactly rod bearings are or what purpose they serve. Generally, a rod bearing’s main job is to help hold the spinning shaft in the engine and lubricate it for proper operation. 

A rod bearing is made up of two halves. The semi-circle-shaped top half has a pinhole, which lets lubricant inside. This reduces friction within the shaft, allowing for free rotation. 

Why Are Rod Bearings Important?

If you have worn down rod bearings, your spinning shaft will not get the lubrication it needs. This can cause a plethora of issues, and it may severely damage your engine over time. 

One of the biggest potential issues with worn rod bearings is spun bearings. When this happens, the bearing welds itself to the crankshaft and spins along with it. This can lead to oil starvation, as well as metal shavings inside your engine oil. 

For this reason, it’s essential to replace your rod bearings as soon as you notice signs of wear. The longer you wait, the more severe the damage will become. 

Symptoms of Worn Rod Bearings

There are a few signs that let you know to replace your rod bearings. If you notice any of the following symptoms, have your bearings checked out:

• Rod knocks
• Transmission noise
• Reduced oil pressure

Rod Knocks

When your rod bearings wear out, the space between them and the connecting rods wears out. This can cause the ends to bang against the crankshaft, leading to a banging noise called “rod knocks.”

If you notice any knocking or banging noises coming from underneath the hood, your rod bearings are likely the cause. 

Transmission Noise

The thrust bearing face, one of two types of bearing faces, will deteriorate over time. This can cause the crank to force the torque converter into your transmission, leading to noises. If it isn’t taken care of in time, it can also cause transmission damage. 

Reduced Oil Pressure

The extra clearance that worn bearings cause can result in oil pressure loss. This loss is most severe at low RPMs when the shaft is spinning slowly. In some cases, your oil light may turn on to alert you of this issue.

How to Replace Your M3 Rod Bearings

You’ve weighed all your options and decided that you’re comfortable replacing your own rod bearings. Now, where do you begin? 

The first step is to gather the tools and materials for the job. The table below lists everything you’ll need to replace your bearings successfully.

Make sure you use the correct size and type of rod bearings for your engine. If you don’t know exactly what to get, consult your M3 manual or ask a mechanic at the dealership. Once you have everything you need, you can begin the replacement process. 

1. Remove anything in the way of the crankshaft assembly, where the rod bearings are located. There are many nuts and bolts to unscrew, so be sure to mark and store them properly as you take them out.
2. Once you can access the rod bearings, use your soft rubber mallet to gently tap them out. Be sure to tap only the top edge, never the sides. 
3. Before you install the new rod bearings, use your degreaser or mineral spirits to clean everything you removed from the crankshaft. This will ensure each part is free of contaminants, which could cause more rod bearing issues in the future.
4. Now that everything is clean, you can install the new rod bearings. Work in reverse order of the disassembly process, and put a small amount of engine oil in each new bearing before you put it in place. 
5. Once the new bearings are in place, replace everything you removed. 

Final Thoughts

Rod bearings are an essential part of your M3. They wear out over time, and when they do, you’ll need to replace them as soon as possible to prevent further damage.

Depending on where you go, your rod bearing replacement will cost $2,000-$3,500 on average. BMW dealerships will always charge higher prices than independent shops, and estimates can range up to $9,500 after all is said and done.