9 Common & Serious BMW M47 Engine Problems (18d, 20d)

BMW diesel engines are my forte here at Lifeonfour, our extensive reviews of BMW diesel engines are amongst our most read articles. Today, I’m diving deep into every possible problem of the BMW M47 diesel engine.

I won’t keep you hanging, here are the most common BMW M47 engine problems:

  • Swirl Flap Failure
  • Turbocharger Failures
  • Glow Plug Failure
  • Injector Failures
  • Fuel Pump Failure
  • EGR Failures
  • Crank Pulley Failure
  • PCV Valve Failure
  • Vacuum Leaks

Want to learn more? Don’t go anywhere. As I continue, I’ll first reveal some more M47 engine specifications and right after that, I’ll jump into all the details of the concerns I listed above.

Basic BMW M47 Engine Specs

Let’s first learn more about the specs of this engine and see what kind of specifications this engine delivers. 

The M47 engine is an inline-4 turbo diesel engine produced by BMW between 1999 and 2007. This engine is probably one of the most mass-produced inline-4s that BMW ever made.

This engine uses a cast iron block and an aluminum cylinder head. The M47 engine at first used old-school technology but as the years progressed it was adapted for newer stuff.

For example, the original engine used a Bosch VP44 fuel pump. But in the later revisions from 2003, this engine started to use common rail diesel injection. This made the engine more reliable because the older VP44 fuel pump was junk that often broke down and caused problems.

The newer models also featured swirl flaps on the intake manifold. And unlike the common rail system, this was a drawback because these things often break down.

What is interesting is that this engine was also adapted for transverse applications. These engines are known as the M47R and were used in Rover and MG models.

Now let’s share the common specs of this engine.

  • Configuration: inline-4
  • Displacement: 2.0L
  • Bore: 84 mm
  • Stroke: 88 or 90 mm
  • Block Material: Cast Iron
  • Head Material: Aluminum
  • Head Design: DOHC, 4 valves per cylinder
  • Turbocharger: Yes
  • Horsepower: 114 – 161 hp
  • Torque: 265 – 340 N-m (195 – 251 lb-ft)

Common BMW M47 Engine Problems

I listed the common problems with the M47 engine, now let’s move on and further elaborate on all of these issues.

Swirl Flap Failure

The first problem on our list is the swirl flap failure that happens on these M47 engines. This problem is not widespread, though it is serious and common enough that we have to mention it.

This engine only affects the M47D20TU variation of the engine. This is a newer engine introduced in 2001. It featured a revised intake manifold with swirl flaps that are actuated by the computer.

They are all attached to a single rod and the design is rather flimsy. The screws that are holding the flaps can fall down into the cylinders and cause carnage.

Also, the flaps can clog up with carbon and malfunction. The best way to deal with these issues is to remove the flaps permanently. Or rebuild the flaps, there are some kits out there that you can use to install new flaps and make them work properly.

Turbocharger Failures

Turbocharger failures are another very common pain point for the M47 engine. These engines are using a single turbo that over long use and abuse can fail.

Whenever the turbocharger fails, you will see the check engine light, there will also be whistling sounds from the turbo and a loss of boost.

The solution to this problem is to rebuild the turbo, there are a ton of shops out there that are doing these rebuilds and once they rebuild the turbo, the component will be as good as new.

Unfortunately, this isn’t very cheap since there is a lot of work in order to solve this problem. So, beware of the symptoms of a failing turbo before you buy one of these engines.

Glow Plug Failure

Glow plugs are another item that often fails on these diesel engines. And these glow plugs are a real pain to get removed.

This is mainly due to the fact that they have basically welded in throughout the long years of usage. Removing them can be a daunting task.

Usually, when they fail they start to show the glow plug light on the dash. You will also have some difficulty starting the engine in the winter because glow plugs are heaters that allow diesel to be ignited at extremely cold temperatures.

Now let’s move on to the next BMW M47 engine problems.

Injector Failures

Injector failures are also extremely common on the M47 engine. This engine used standard diesel injection before 2003 and after the engine implemented common rail injection.

Common rail injectors are far more advanced, and they tend to fail more often compared to the older injectors.

These tend to fail because they are very sensitive to bad fuel. Many people think that they can run these engines on vegetable oil but this is not the case with the common rail engines.

The injectors tend to fail and when they fail they are extremely expensive to fix on the common rail version. That’s why we advise that you add high-grade diesel if you don’t want to damage the injectors.

Fuel Pump Failure

The older non-common rail version of this engine uses a Bosch VP44 fuel pump that is notorious for failing.

Every engine that has this pump has problems. It is a very poor design that plagues this engine with tons of issues and the only way around is to rebuild this pump or replace it.

This is another very expensive item to sort out. Symptoms associated with this problem include the inability to start the engine and the engine stumbling and bucking through the gears. Overall, driving with a bad VP44 pump is a total nightmare.

EGR Failures

The EGR is another big headache for the M47 engine. So, what is the EGR, and what type of task this valve has?

This is the Exhaust Gas Recirculation valve, this valve has a task to recirculate some of the exhaust gasses back into the intake in order to reduce NOx particles.

NOx is very harmful for the people who breathe it and that’s why these systems were invented. But the problem is that all of these systems clog up with carbon.

It is recommended that you clean the EGR regularly if you don’t want to have issues down the line. Symptoms like check engine light, low power, and limp mode are common when the EGR is clogged up.

Crank Pulley Failure

Another very common issue is the failure of the crank pulley. This component is also known as the harmonic balancer.

What this component does is drive the serpentine belt and also act as a balancer of the crankshaft. This component sits at the bottom where the crankshaft is located.

These crank pulleys are made out of rubber and rubber breaks over time. So, if the rubber part fails, you will lose the accessories and the engine will stall.

So, if you notice that the crank pulley wobbles, it is important to replace it before it fails completely.

PCV Valve Failure

The PCV valve or crankcase ventilation breather as some people call it can also fail. This component clogs up and stops working.

It doesn’t ventilate the positive crankcase pressure and you have a problem. This can cause a situation where there will be some blown seals and gaskets on your engine.

Engines even consume engine oil when the PCV valve is failed. That’s why we recommend replacing this part before it creates more problems.

Vacuum Leaks

And the last problem on our list of issues with the BMW M47 engine is the vacuum leaks. Vacuum leaks are a problem with this engine.

These engines use some cheap quality vacuum hoses that can snap pretty easily and then you have symptoms such as check engine light and rough idle. The solution is to upgrade these hoses with new ones and this would solve the issue.

Which Models Have The BMW M47 Engine?

  • 1999 – 2005 BMW E46 320d
  • 2001 – 2005 BMW E46 318d
  • 2000 – 2003 BMW E39 520d
  • 2005 – 2007 BMW E83 2.0d
  • 2004 – 2007 BMW E87 118d
  • 2005 – 2007 BMW E90/91 318d
  • 2005 – 2007 BMW E60/61 520d
  • 1999 – 2005 Rover 75
  • 2001 – 2005 MG ZT
  • 2001 – 2006 Land Rover Freelander


What Are The Common BMW M47 Engine Problems?

Common problems with this engine include vacuum leaks, failed injectors, failed turbocharger, problems with the VP44 fuel pump on the older non-common rail model, EGR failures, and crank pulley failures.

Is The BMW M47 Engine Reliable?

Overall, it is a reliable engine, besides some known issues like the turbocharger failure and the VP44 fuel pump failure on the non-common rail models. Newer engines that use common rail are more bulletproof and do not have such issues.

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