6 To-be-Expected BMW M67 Diesel Engine Problems (40d, 45d)

Are you looking to buy a true big boy diesel? Well, thw M67 engine from BMW could definitely be named as a diesel for true diesel lovers. I had the pleasure of driving one as a luxury rental, and let me tell you, I cried when I returned it.

Not a fan of reading? Here’s a quick recap of this long article.

Common BMW M67 engine problems include:

  • Injector Failure
  • Turbo Failure
  • Swirl Flap Failure
  • Clogged EGR Valve
  • DPF Failure
  • PCV Valve Failure

First, we are going to learn more about the specs of this engine, then we are going to discuss the common BMW M67 engine problems and learn more about the issues this model carries. Lastly, we will learn more about the models that have this engine. So, let’s get started.

Basic BMW M67 Engine Specs

Now, before we dive into the problems of the M67 engine, let’s first learn something more about the specs and see what numbers this engine is pushing. Specs are really important, especially for people who want to buy a car with this specific engine.

The M67 is a V8 diesel engine that was designed specifically for the big 7 Series models by BMW sold between 1998 and 2009. Then this engine was replaced by the N57.

What is interesting about the M67 is that this engine was one of the first engines that implemented turbocharging and common rail diesel injection. This made this engine pretty revolutionary at that time and attracted a lot of attention because of these technologies which made diesel the engine of choice in Europe.

The M67 comes in two variations, a 4.0L and a 4.5L. The main difference between the two is the displacement and the block material. The 4.0L block was made out of cast iron, while the 4.5L engine was made out of aluminum. This material made the 4.5L about 30 kilograms lighter, although it has a bigger displacement.

The 4.5L was a big refinement of this design and these engines were released after 2005.

But here are the full specs of this engine.

  • Configuration: V8
  • Displacement: 4.0L, 4.5L after 2005
  • Bore: 84 mm, 87 mm
  • Stroke: 88 mm, 93 mm
  • Block Material: Cast Iron, Aluminum after 2005
  • Head Design: DOHC, 4 valves per cylinder
  • Turbocharger: Yes
  • Fuel Injection: Common Rail
  • Horsepower: 235 – 326 hp
  • Torque: 560 – 750 N-m (413 – 553 lb-ft)

Common BMW M67 Engine Problems

We listed the most common BMW M67 engine problems at the beginning of this article, now let’s move on and further elaborate on these problems.

Injector Failure

The first problem and probably the most common one is injector failure. So, why is this an issue with the M67 engine?

Well, this is a common diesel engine problem. Diesel engines have issues with their injectors. Specifically common rail diesels that are the most prevalent nowadays.

These engines are using very sophisticated injectors that inject fuel at extreme bar/PSI of pressure. So, we can say that they go through a lot during their life.

And they can eventually fail, either from mileage or from bad fuel. Both situations can kill the injectors.

What is good though is that you can rebuild them. And this is the more recommended route than replacing them because doing a replacement will cost you a fortune.

Sometimes this service can cost more than these 20-year-old cars that have this engine. So, better watch out for these injectors because they are expensive to fix.

Turbo Failure

Turbocharger failures are also pretty common on these engines. This is another common problem with these diesel engines.

The M67 uses a twin-turbo setup, which means that you have two turbos on this engine. One per each bank. And both of them tend to fail after the engine reaches 150,000 km.

These turbos can last longer if you change the oil regularly and do the maintenance. But if the engine is poorly maintained and overheats, it can also damage the turbos.

So, the shaft will start to wobble, and the turbo will start producing whistling noises. In addition to this, there can be oil leaks coming from the turbo when it fails.

Overall, the turbo failure is a very expensive problem. The positive thing is that these turbos are also rebuildable. You can rebuild them at a special shop and they will work like new ones.

That’s why we recommend going this route because buying a new turbo can be a pretty expensive thing.

Swirl Flap Failure

The next most common problem with the BMW M67 engine is the problem with the swirl flaps. So, what is a swirl flap, and why is it a problem?

Swirl flaps for those who don’t know are the intake flaps on diesel engines. Diesel engines do not have throttle bodies like gasoline engines and they use swirl flaps that open and close. All this is done by a special actuator.

What happens on these diesel engines is that the intake manifolds get full of carbon. And this soot will simply ruin the flaps. It will make them malfunction and cause a ton of issues.

The solution is to clean the intake very often. And this is something that nobody does. So, the swirl flaps have to go and be permanently removed in order not to have issues.

This can cause certain problems and the fuel economy might drop a bit. So, you have to be prepared for this or simply replace the intake manifold with a new one. This can be pretty expensive.

Clogged EGR Valve

Another very common problem that happens on many diesel engines including the M67 engine is the problem with the EGR.

So, what is the EGR? The EGR is the exhaust gas recirculation valve. This valve recirculates some of the exhaust gasses back into the intake manifold.

What is bad is that this EGR valve is really easy to clog up with carbon. These valves can fail as low as 30,000 km.

So, this is why it is recommended that you regularly clean the EGR valve. And this is also another thing that no owner does and they eventually end up with a clogged EGR.

There are also some other symptoms such as the check engine light, rough engine work, and limp mode.

The solution is to delete the EGR or replace it with a new component. Deleting it might fail your emissions testing.

DPF Failure

Another fairly common problem with this engine is DPF filter blockages and failure. For those who don’t know, the DPF is the diesel particulate filter.

Newer versions of this engine have this DPF and only on these models the DPF this is a problem. This is another emissions device that traps the soot.

Then when you are cruising on the highway and the DPF is full, it has to be regenerated. Or simply said, cleaned. This component cleans itself by injecting diesel and burning off the soot.

What many people don’t do is not regenerate the DPF. They drive like that for long periods of time and the DPF will simply clog up.

The solution to this problem is to manually clean the DPF or remove it completely from the car. This will also ruin the emissions performance and will make you fail the emissions testing.

PCV Valve Failure

The last problem on our list is the PCV valve failure. So, what is the PCV valve, and why is it a problem?

Every engine has a PCV valve, which is the Positive Crankcase Ventilation valve, this valve collects the oil vapors inside the crankcase and purges these gasses into the intake.

What can happen is that this valve can fail and you can start experiencing oil consumption. This problem can also cause your engine to leak all over. Mainly because the pressure will want to escape from somewhere and the easiest place is the gaskets.

Luckily, replacing it is not expensive and can be done fairly easily.

Which Models Have The BMW M67 Engine?

  • 1999 – 2001 BMW E38 740d
  • 2002 – 2005 BMW E65 740d
  • 2005 – 2009 BMW E65 745d
  • 1999 BMW Z9 Concept


What Are The Common BMW M67 Engine Problems?

This engine does not have serious problems, mainly common diesel issues. Things like injector failures, turbocharger failures, clogged EGR, clogged DPF, swirl flap failures, and PCV valve failures are common.

Is The BMW M67 Diesel Engine Reliable?

Yes, this engine is very reliable, if you find a good example, with plenty of maintenance history, and you maintain it well going forward, this engine would easily last for 500,000 km.

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