6 Common BMW B38 Engine Problems (16i, 18i)

Common BMW B38 engine problems include:

  • Vibrations On Idle
  • Crankshaft Bearing Failure
  • Carbon Buildup
  • Coolant Leaking From Turbo
  • Water Pump & Thermostat Failures
  • VANOS Failures

Are you interested in learning more about the BMW B38 engine problems? If that is the case, you are in the right place because, in this article, there will be a lot to cover on this engine.

Common BMW B38 Engine Problems Explained

We covered briefly the problems this engine has, now let’s discuss them more in-depth.

Vibrations And Noise On Idle

The most common problem with these engines is the appearance of vibrations and noise. These engines tend to vibrate a lot and often make the driver and the passengers uncomfortable. So, why is this the case?

These engines are inline-3. This means that they are not well balanced. The smaller the engine is, the greater the vibrations are.

The most well-balanced engines are the inline-6 B58s that BMW makes. The B38 has the same bore and stroke as the B58. But because of the lack of pistons, it tends to be noisier as well as to produce more vibrations.

So, before you decide to buy a car with one of these engines, you should keep this in mind. These engines tend to produce more noise and vibrations.

This doesn’t mean that the engine is bad. This is a completely natural thing for these engines. So, you shouldn’t be worried much about it.

Crankshaft Guide Bearing Failure

When it comes to serious problems with the B38 engine, we couldn’t avoid listing the crankshaft guide bearing failure.

On some of these engines, the crankshaft guide bearing can wear out prematurely. This situation can cause the clutch pedal to malfunction while shifting.

When this happens, you will get a check engine light and noise from the transmission bell housing. Even though in some cases, there can also be engine damage. But this happens more rarely.

The affected vehicles by this problem are the F55 and F56 chassis cars produced between December 2014 and June 2015. These are the Mini Cooper 4-door hardtop models.

There was a special recall on these models issued by the NHTSA and a special bulletin on how this problem should be tackled. More on that, you can check in the following link.

Overall, try to avoid these models produced between December 2014 and June 2015. Or if you want to buy one of these cars, make sure that the problem was patched.

Carbon Buildup

Another very common problem with these engines is carbon buildup. What is carbon buildup and why does it appear?

These engines implement a technology that is known as direct injection. Direct injection was primarily used in diesel vehicles, but it found its way into gas-powered engines in recent years.

Mainly because this way of injecting gas gives better fuel economy. Instead of injecting the gas through the intake ports, gas is injected from the top of the cylinder with help of a high-pressure fuel injector.

And because of this way of injecting gas, the intake ports are starting to collect carbon deposits. These carbon deposits can eventually cause the valves not open and close correctly.

This will result in engine misfires and check engine light. This is why it is recommended that you do a procedure known as walnut blasting every 60,000 miles or so, to clean the valves from these carbon contaminants.

By doing this preventive service, you will make sure that the engine will not suffer some running issues in the long term.

Coolant Leaks From Turbo

Another very common problem with this engine is the coolant leaks that develop from the turbo. Two coolant lines go to the turbo of the engine.

These lines are held by O-rings. And over time, these O-rings fail and cause coolant to leak from the turbo.

These are small leaks but if you have leaky hoses, you will notice some greenish contaminants between the hot side and the cold side of the turbo, right at the place where these two steel hoses attach.

So, if you lose some coolant and you don’t know where the coolant goes, it is worth checking the turbo out and making sure that there are no leaks.

If there are leaks, you will have to replace the O-rings with new ones and top off the coolant levels.

Water Pump & Thermostat Failures

Water pumps and thermostat failures are common on BMWs and the B38 engine is no exception to this. Even so, it happens to a lesser extent compared to other BMW engines from the older generation.

The recommended time to replace these water pumps is about 5 years or so. After that, they tend to degrade, start leaking and cause all sorts of problems. Overheating is the most serious problem.

So, if you have high temperatures and bluish leaks of coolant on the ground, it is definitely worth addressing this problem. If you don’t do so, the engine could end up being damaged and even completely fail.

VANOS Failure

The last problem on our list is the VANOS failure. As you know, VANOS is BMW’s variable valve timing system.

This system is regulated by VANOS solenoids and in many cases, these solenoids can cause problems and turn on the check engine light. In more serious situations, your car can also go into limp mode.

Which Models Have The BMW B38 Engine?

Now let’s learn which models have the BMW B38 engine. We will cover all major variations and sub-variations of this engine.

B38A12U0 55 kW version

  • 2014–Present F55/F56 Mini One First

B38A12U0 75 kW version

  • 2014-2018 F55/F56 Mini One

B38A15M0/B38B15M0 until 2018. B38A15M1/B38B15M1 after 2018.

75 kW Model

  • 2015-Present BMW 216i F45/F46
  • 2018-Present Mini One F55/F56

80 kW Model

  • 2015-2019 BMW 116i F10/F21

100 kW Model

  • 2015-2019 BMW F20/21 118i
  • 2015-Present BMW F22/23 218i coupe & convertible
  • 2014-Present BMW F45/46 218i Gran Tourer & Active Tourer
  • 2015-2019 BMW F30/31 318i
  • 2015-Present BMW F48 X1
  • 2014-Present Mini Cooper F55/56/57
  • 2015-2019 Mini Clubman F54
  • 2017-Present Mini Countryman F60
  • 2017-Present BMW F39 X2
  • 2017-Present BMW F45 225xe
  • 2019-Present BMW F40 118i
  • 2019-Present BMW F44 218i
  • 2020-Present BMW F39 X2 xDrive25e


  • 2013-2020 BMW I12 i8
  • 2020-Present Karma Revero GT/GTS

Basic BMW B38 Engine Specs

Now let’s start with the BMW B38 engine specs and learn the general specs of this engine, as well as the different variations of the engine.

What is worth noting is that this engine is a modern inline-3 turbocharged gasoline engine from the BMW family of modular engines. This engine replaced the N13 that was previously used and borrowed from PSA.

The displacement of the B38 engine varies between 1.2L and 1.5L depending on the application. There are a few different variations of the engine. And these are the following.

  • B38A12U0

This is the 1.2L version of the engine and has two subversions The first version makes 55 kW (74hp) @ 4,000 rpm and 150 N-m (111lb-ft) @ 1,400 rpm. And the second makes 75 kW (101hp) @ 4,250 rpm and 180 N-m (133lb-ft) @ 1,400 rpm.

  • B38A15M0/B38B15M0 (B38A15M1/B38B15M1 after 2018)

This engine is 100kW (134hp) @ 4,400 rpm and 220 N-m (162lb-ft) @ 1,250 rpm. The 2018 update bumped the specs by a small margin and this engine makes 104 kW (139hp) @ 4,400 rpm and 220 N-m (162lb-ft) @ 1,250 rpm.

  • B38K15T0

This is the most powerful version that creates 170 kW (228hp) @ 5,800 rpm and 320 N-m (236lb-ft) @ 3,700 rpm.


What Are The Common BMW B38 Engine Problems?

This engine does not have any major design flaws or serious issues. The most notorious problem is the crankshaft guide bearing that can fail. There was a recall on this specific problem. Other problems might include coolant leaks, water pump and thermostat failures, carbon buildup, and VANOS failures. Overall, the engine is pretty decent.

Is The BMW B38 Engine Reliable?

This is probably one of the most reliable small displacement engines that BMW produced. The engine does not have any major issues whatsoever and compared to its predecessors, we can say that it is very good. There are minor problems like coolant leaks, VANOS issues, and carbon buildup. But these problems are not that serious and affect the overall reliability of the engine.

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