8 Big BMW N43 Engine Problems From an Owner’s Perspective

My experience with the N43 engine is actually not with a BMW, it’s with a Peugeot. Yes, that’s right. BMW shared their N43 engine with the PSA Group (Peugeot and Citroën) and they named it the 1.6 VTI engine.

Common problems of the BMW N43 engine include:

  • Spark Plug & Coil Failure
  • Carbon Buildup
  • Injector Failure
  • HPFP Failure
  • Timing Chain Problems
  • VANOS Problems
  • NOx Sensor Failure
  • Water Pump & Thermostat Failure

Want to learn more? Continue reading.

That being said, a close friend of mine owned a BMW E90 318i (shown in the cover image above) with this engine for several years, so I’m reporting on all the problems he experienced during his time of ownership.

First, we are going to learn more about the specs of this engine, then we will cover all the BMW N43 engine problems and see what troubles this engine the most. Lastly, we are going to learn more about the models that include these engines. So, let’s dive into the topic.

Basic BMW N43 Engine Specs

First, let’s take a look at the basic specs of this engine.

The BMW N43 engine is a gasoline engine that was produced by BMW between 2007 and 2011. It was a very short-lived engine designed specifically for entry-level models. Its quick demise was mainly because the market was shifting towards turbocharged engines, and it was replaced by the N13 engine, which is a turbo engine.

So, as you probably assume, the N43 is a naturally aspirated engine. This engine is inline-4 which means that there are four cylinders. It came in two types, a 1.6L and a 2.0L version. The block, as well as the head, were made out of aluminum, making the engine pretty lightweight.

The head design is DOHC with four valves per cylinder. This engine also uses very advanced technologies such as VANOS. In fact, this engine has double VANOS, both on the intake and exhaust camshaft. The engine also uses direct injection, which further increases the efficiency but also has brought some problems.

What is interesting about the N43 is to note that this engine was not sold in countries where there is high sulfur content in the gasoline. The N43 also does not have Valvetronic, which is another main cause of problems in other BMW engines.

Here are the specs of the BMW N43 engine.

  • Configuration: inline-4
  • Displacement: 1.6L or 2.0L
  • Bore: 82 or 84 mm
  • Stroke: 75.7 or 90 mm
  • Block & Head Material: Aluminum
  • Head Design: DOHC, 4 valves per cylinder
  • Variable Valve Timing: Yes, Dual VANOS
  • Direct Injection: Yes
  • Horsepower: 121 – 168 hp
  • Torque: 160 – 210 N-m (118 – 155 lb-ft)

Common BMW N43 Engine Problems

We listed the common BMW N43 engine problems, and now it is time to further elaborate on each one of them, so keep up with us while we explain every problem in detail.

Spark Plug & Coil Failure

The first and most common problem with the N43 engine is the spark plug and coil failure. Both of these ignition components tend to suffer a lot on these engines.

This is the case because the coils that BMW used are pretty bad, and they even had a recall on these ignition coils.

Symptoms associated with this problem include check engine light, engine misfires, poor engine work, and poor fuel economy.

The engine will not be happy whenever you have problems with these ignition components. And the easiest way to test the specific coil is to simply swap them out. If the check engine light code moves to the next cylinder this is causing your problem.

Carbon Buildup

Carbon buildup is another big problem with this BMW N43 engine. So, why is this a problem on this engine?

Well, this engine uses direct injection. This type of injection uses a different method of injecting gas compared to the port injection used previously.

So, the intake valves are not cleaned as they usually were in older engines. Over time oil vapors start to stick to the valves and create carbon deposits.

These deposits can become very excessive and cause the valves to malfunction. This will lead to misfires, loss of compression, and loss of power. The solution is to do a method called walnut blasting every 60,000 km in order to be safe from these problems.

Injector Failure

Injector failures are also very common on the BMW N43 engine. This engine as we noted previously uses direct injection.

This method of injecting uses special sophisticated piezo crystal injectors that are rather sensitive. They tend to fail quite often and they are almost impossible to rebuild.

Replacing them can be pretty expensive. That’s why we would advise that you make sure that the injectors are in good shape before you buy one of these cars with these engines. Read our guide on fuel injector issues to learn about the symptoms of bad fuel injectors.

HPFP Failure

In addition to the new injectors, this direct injection system also uses a secondary high-pressure fuel injection pump (HPFP). This secondary injection pump is notorious for failing.

When it fails, it can start producing strange symptoms. Namely, check engine light, engine stalling, hesitation, poor fuel economy, fuel leaks, and noises.

It is recommended that you replace this pump with a new unit. Although some of them can be rebuilt. So, if you want, you can go this route.

Timing Chain Problems

Timing chain problems are also very prevalent on these N43 engines. And they can come from a variety of different places.

The first issue is the case when the timing chain gets stretched. This will cause engine rattle and if not addressed, the chain will jump and ruin the engine.

The chain guides also wear a lot and release debris that ends up in the oil passageways, and this will prevent oil flow. Leading to engine failure in the process.

Lastly, the timing chain tensioner can fail. Causing problems and making the chain loose.

Overall, this engine is pretty much a nightmare considering these problems with the timing chain.  Only regular oil changes can somewhat delay these issues and make the engine last a bit longer.

VANOS Problems

VANOS problems are also common on this engine. For those who don’t know, the VANOS system is the variable valve timing that this engine has.

There are two solenoids, one on each camshaft. They tend to fail and cause issues. The most common will be the check engine light. But there can also be other symptoms like loss of power and poor fuel economy.

Luckily replacing these components is not crazy expensive since these are only solenoids. In other words electronic actuators.

NOx Sensor Failure

Another big issue with this engine is the NOx sensor failure. So, what is a NOx sensor, and how is this a problem?

The NOx sensor is a special sensor on these direct injection engines that is designed to measure the NOx particles in the exhaust.

So, the mounting position is on the exhaust of the car, somewhere in the middle right where the B-pillars go but from underneath the car.

What can happen is that this sensor can fail and when it fails you will have the check engine light, poor emissions, rough engine work, misfires, and high fuel consumption.

Now let’s move on to the next BMW N43 engine problems.

Water Pump & Thermostat Failure

The last problem on our list of issues with the BMW N43 engine is the problem with the water pump and thermostat.

These two components tend to fail a lot. Especially the thermostat. This component can fail in two positions. Either closed or open. If it’s closed the car would constantly overheat. If it fails in a cold position, this engine will be very difficult to get to temperature.

The water pump on the other hand can also cause problems. Namely, noises and also leaks. It can perform so badly that the engine will constantly overheat.

So, if you notice one of these symptoms, you will have to replace the bad component.

Which Models Have The BMW N43 Engine?

  • 2007 – 2009 BMW E81/82/87/88 116i
  • 2008 – 2011 BMW E81/87/88 118i
  • 2007 – 2011 BMW E90/91/92/93 320i
  • 2007 – 2009 BMW E60/61 520i


What Are The Common BMW N43 Engine Problems?

Common problems with the BMW N43 engine include coil failures, carbon buildup, injector failure, HPFP failure, water pump failure, thermostat failure, timing chain stretching, timing chain guide failure that causes oil starvation, VANOS problems, and NOx sensor failure. Overall, this is a pretty problematic engine.

Is The BMW N43 Engine Reliable?

The short answer is no. This is probably one of the worst engines that BMW made. BMW did not put a lot of effort into building and testing this engine. It has a ton of problems that can be a nightmare to fix. That’s why you should avoid it.

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