Common problems with BMW m340i

BMW m340i Problems

The BMW m340i is a compact executive car with lots of outstanding features, advanced technology, and excellent performance. But as expected, this luxury sedan from BMW also comes with a ton of common issues that users should be ready to deal with. But what are the common problems with the BMW m340i?

Common problems with the BMW m340i are engine stalling, coolant loss, electrical problems, bad VANOS Solenoids, faulty fuel pressure, faulty seatbelt assembly, faulty oxygen sensor, and faulty valve cover gasket. Despite having several problems, the m340i is fitted with a reliable engine.

What are the common problems with the BMW m340i?

Engine stalling

One of the first issues that BMW m340i users should be ready to encounter is engine stalling. Signs of a stalling engine are a bad coolant sensor, lack of fuel, and a dead alternator. Some of the things that make the BMW m340i’s engine stall are a bad fuel system, faulty ignition system, and bad air intake system.

So, if your car engine is stalling, have a professional mechanic inspect it and fix the problem.

Electrical issues

Electrical problems are common in the BMW m340i xDrive. Despite having several electrical issues, the connection between the 48-volt battery and starter generator is the main electrical problem. This connection may have undergone an improper assembly, which can lead to increased electrical resistance at the connections.

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The good news is that BMW recalled the cars with this problem and they were fixed for free. So, if you’re buying a used BMW m430i, ensure the owner fixed this issue if it had one.

Faulty valve cover gasket

The valve cover gasket becomes faulty or bad because of the cheap rubber that it comes with. Therefore, after the BMW m340i covers at least 70,000 miles, you should start inspecting the valve cover as it will break down and start leaking oil.

One of the main reasons why the rubber valve cover gasket wears out faster is due to the constant heating and cooling that it experiences. Some of the signs of a bad valve cover gasket are low engine oil light, burning oil smell, and smoke from the valve cover area. Fix this problem by replacing the bad valve cover gasket.

Coolant loss

Another common problem with BMW m340i models is coolant loss. However, users and mechanics have not pinpointed the cause of coolant loss. This is because most BMW m340is with this problem don’t have water pump issues, a cracked hose, or a faulty radiator. 

Nonetheless, signs of coolant loss are overheating engine, coolant loss, visible leaks, and coolant mixed with oil. Ensure there is enough coolant and fix the underlying issue to avoid coolant loss.

Faulty oxygen sensor

 A faulty oxygen sensor should be replaced immediately as it can cause the car to fail an emissions test. Symptoms of a bad oxygen sensor are misfiring, low fuel mileage, engine stalling, or even rough idling. Replace the bad oxygen fuel sensor to fix the problem.

Bad VANOS Solenoids 

This is a common problem for BMW drivers with a modern turbo BMW engine. This issue has been in existence since 1992 and it can also be found in the latest B58 engines like the m340i. VANOS usually fails on BMWs and they are somewhat easy to fix.

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However, the VANOS Solenoids on the B58 are located next to the timing chain, at the back of the engine. So, fixing this problem is somewhat challenging. Some of the signs of bad VANOS Solenoids are rough idle, power loss, poor fuel efficiency, and VANOS fault codes. Fix this issue by replacing the bad VANOS Solenoids. 

Faulty fuel pressure sensor

This is another vital part to look out for on your BMW m340i as you cover more than 80,000 miles. A bad fuel pressure sensor will lead to a failing fuel temperature, check engine light comes on, poor performance, and engine misfire. Replace the fuel pressure sensor in time to avoid such issues.

Faulty seatbelt assembly

This is a manufacturer defect. Some cars that had this problem were recalled and fixed. The bolt securing the seat belt assembly to the frame was not tightened as required. Ensure this problem was resolved if you’re looking to buy a used BMW m340i.


Is the BMW m340i reliable?

According to BMW standards, the BMW m340i is a reliable car. But when you compare it with most of its competitors from Mercedes-Benz and Audi, you will find that it is less reliable. Nonetheless, most reliability agencies give it a rating of slightly above average, which is better than most BMWs.

Is it expensive to maintain a BMW m340i?

While the BMW m340i is cheaper to maintain than a BMW x1, it is still costlier to maintain. Besides, it is one of the cheapest BMWs to maintain compared to the BMW 7-Series, 5-Series, and 1-Series. The BMW m340i is costlier to maintain as BMW parts and services are also expensive. 

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What is the high mileage for the BMW m340i?

Since the BMW m340i has been on the market for less than 5 years, it is quite challenging to know its high mileage. But when we compare it with other BMW 3-Series models, it is likely the high mileage for the BMW m340i will be between 100k and 150k miles. So, if you want to buy a reliable used m340i, consider one with less than 100k miles.

After how many miles does the BMW m340i start having problems?

Like most BMW 3-Series, the BMW m340i starts having minor issues when it clocks over 30,000 miles. Things like spark plugs and ignition coils are the first to be replaced or repaired. On the other hand, serious issues start showing up when the car clocks over 100,000 miles.

How reliable is the BMW B58 engine?

Yes, the BMW B58 is among the most reliable BMW engines on the market. That’s why even reliable cars from Toyota, such as Toyota Supra use the B58 3.0-liter turbo engine. Aside from being reliable, this engine is also powerful and durable.


Now that you know some of the common problems that the BMW m340i faces, maintaining this car shouldn’t be that difficult. Most of the issues mentioned above are easy to avoid as long as the car is well-maintained.

All in all, the BMW m340i is a nice compact executive car with many high-end features. It is also comfortable, luxurious, and performs outstandingly.

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Edwin Odipo

Why do you love writing about cars? Cars make our lives easy. You can visit your distant friend, relative or even rush to the grocery store a few miles from your home with a lot of ease. Imagine how life was before the invention of cars?? To me, cars are a blessing that made life more convenient.

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