Owning a car with the letters “B, M, W” on it is probably the dream of everyone on this planet. However, it is important to know both the good things and bad things about a car before choosing to buy it. Hence, this post is dedicated to the common faults that you may find in a BMW 3 series car.

The most common faults in a BMW 3 series are related to the fuel pump, fuel injectors, water pump, and coolant leaks. Apart from this many users have also complained about rattling noises coming from the engine bay and their tyres wearing out too fast.

Unfortunately, the solution for most of these problems is to replace the damaged parts. However, you can try to prevent these problems from occurring in the first place or increase the life of these parts at the very least.

Read on to find out the causes of these problems and some possible preventative measures that might help you out!

Fuel pumps

The most common faults associated with BMW 3 series are related to the fuel pumps. This causes a whole host of problems in your car. Fortunately, most of these problems are rather mild.

For example, you may feel that the engine is vibrating a lot during idling. Other times, you might think that the car is having abnormal spurts of power (or lack thereof) while driving it. At times, it might take a long time for your car to start up. However, the worst-case scenario that you might face is that your car comes to a complete standstill condition.

All these problems are caused by an improper supply of fuel. Unfortunately, this is an inherent problem of BMW 3 series models. Also, no one knows what the exact root cause of this problem is. If you are planning on buying a pre-owned car, then you are better off having the fuel pump changed as soon as possible. This will help prevent the worst-case scenario where you are stranded in the middle of nowhere when your fuel pump finally decides to stop supplying fuel.

Fuel injectors

Like the fuel pump, the fuel injectors in a 3 series also cause regular problems for their owners. These problems are a little less noticeable and may even pass by undetected. Moreover, their impact on your daily driving experience shouldn’t be significant.

For example, you might experience moments of lower power output than desired. Alternatively, there might be some extra emissions or an increase in fuel consumption. Thus, it’s okay to wait for any of these symptoms to show up before you act.

A simple fix for these fuel injectors is to take them out and check the nozzle. They should be cleaned if necessary. However, since some specialized equipment is required for this, it is probably just easier to replace these injectors.

Since the fuel injectors are relatively near the exterior of the engine, it shouldn’t be too hard for anyone who is used to working on engines. Given that these injectors are a common source of problems, it might be best to replace all of them while you are at it.

Coolant pump problems

Just like the fuel pump, another source of common faults in the BMW 3 series is the coolant or water pump. If the water pump is malfunctioning, then you will notice that your engine is overheating. This can have catastrophic consequences if left unchecked. One of the most common ones is engine seizing due to overheating.

The most common cause of a malfunction of water pumps in the 3 series is a breakdown or high wear. Unlike other cars that use a mechanical water pump driven by the engine, the BMW 3 series uses a plastic pump that is driven by the battery. While this is more efficient for the engine, since the blades are made of plastic, they tend to break down more quickly than traditional metal water pumps.

This high wear can be caused by old age, low levels of coolant, or coolant contaminated with rust and other debris. Such conditions increase the stress on the water pump leading to faster breakdowns. Unfortunately, if the water pump breaks down, your only solution is to replace it. Usually, the water pump is replaced every 80000 miles or so. You can extend its life by flushing and replacing the coolant every 20000 miles.

Coolant leaks

Coolant leaks are one of the most common faults found in BMW 3 series models. There are primarily two types of coolant leakages – internal and external.

An internal leak occurs when the coolant leaks into the combustion chamber and burns along with the fuel. It is easy to spot as you might notice white smoke from the exhaust or get a sweetish smell. An external leak will when you see small puddles of coolant accumulated on the ground under a parked car or on different components.

There may be several causes for external leaks, one of which might be the plastic water pump. Due to the high wear of the plastic water pump, there may be leakages spotted around here. Another possible source of the leakage is the coolant reservoir which is placed in the engine bay. Since it is made of plastic too, it is prone to damage and over time it may wear out as well. Hoses can be another source of external leakage, especially if they are around any sharp edges of the engine. For such cases, one needs to simply locate the leakage and replace the part.

Internal coolant leaks on the other hand are generally caused by sealing gasket issues. These can have major consequences if not fixed in time. Thus, if you notice the signs, it is best to ask a professional to take a look as detecting these leaks is a bit tougher than the external ones. Similarly, the solution here is to replace the worn gasket causing the leakage. Often, the cause is found to be the cylinder head gasket in such cases.

Rattling noise

Another problem that BMW 3 series owners regularly complain about is the rattling noise that they hear while accelerating. Most commonly this noise is caused by the action of the fuel injectors. While there is no problem as such with this noise, it can be mildly annoying to some users. Sadly, if you take it to the dealership, they will most likely claim it is not a problem and might just ask you to live with it.

Another possibility for this noise is caused due to the cam chain tensioner. This part is responsible for ensuring that your timing chain doesn’t slip and is known to make a little bit of noise in almost all cars. However, if the noise is noticeable, then there is probably something loose or misaligned there that needs to be checked out.

While there may be other common faults leading to a rattling noise from the engine like a loose heat shield or a misfiring engine, these are rather rare in the BMW 3 series. Hence, they may be explored if the above two options are ruled out as probable causes.

High tyre wear

Finally, the last major problem noted by 3 Series drivers is an unusually high rate of tyre wear. Abnormal tyre wear is generally caused due to a suspension setting or the alignment of your wheels. Thus, if your wheels get misaligned or if you are taking your turns too roughly, then they may get worn out faster than normal. Alternatively, some potholes may also damage the suspension leading to abnormal and uneven tyre wear.

In the case of the BMW 3 Series models, Run Flat Tyres (RFTs) come stock with the car. Unfortunately, there was apparently a bad batch sold (Bridgestone) and thus they were replaced if found to be the case. Moreover, the 3 series models supposedly have an aggressive toe-in configuration in the car for better performance. This generally leads to higher wear on the outer side of the tyres.

While the solution for such worn tyres is to simply replace them, you can increase their life a bit too. This can be done by frequently rotating the tyres around between the different wheels to ensure an even wear on all of them. You might even want to do it more frequently than mentioned in the owner’s manual. While this may seem cumbersome, it will allow you to save some money in the long run.

Final Thoughts

No car is perfect. Even a luxurious car by BMW has its faults. Hopefully, this article helped you learn about the most common faults in a BMW 3 series car. It is important to note that these are some of the problems that you might face, not a certainty. Putting these faults aside, the car is definitely worth the money. But if you are buying a pre-owned vehicle, you might want to check out the problems mentioned in this post. Otherwise, we wish you enjoy going on long drives with your new bimmer!