Most BMW car models are equipped with the famous and very reliable inline-six engine, which is different from the V6. It is a more refined version with a very similar or the same displacement. Also called straight-six engines, the inline is the preferred engine BMWs use. BMW doesn’t produce any models with a simple V6 engine.
Why does BMW use straight-six engines instead of V6?
Nowadays, not only BMW, but many other manufacturers like Land Rover and Jaguar are also turning toward using the inline-six engine instead of a V6. These two engine options are very similar with the same displacement of 3.0 L.
Mercedes-Benz has also switched toward straight-six engines, instead of utilizing V6. There should be a reason for that. Can the difference be felt behind the wheel?
Is the Inline-six engine used in BMWs better than a V6?
The inline-six engines used in most BMWs are better than a V6 for various reasons. It is a more refined version with the same amount of displacement.
Smoother and less vibrating
The combustion strokes in each cylinder get rebalanced by another cylinder, which goes through an induction stroke. This makes the cylinders paired and that results in a lot less vibration generated by the engine due to the symmetric relocation of the cylinders.
Which engine sounds better? V6 or Inline?
The exhaust of straight-six engines is generally much more satisfying than the standard V6 counterpart. The main reason for that is that you have all six exhaust ports on the very same side of the engine, making them feel more synchronous. This way you get a harder sound with each pulse.
Performance comparison
In terms of performance, the inline (straight) six engine allows for much more space, in order for you to upgrade the vehicle or put a performance enhancer under the hood. Such devices can be turbochargers, associated plumbing, or even superchargers.
V6 engines, on the other hand, lack the room to fit in anything and you need to search for space between cylinder heads, or somewhere on the side of the engine. This makes things very complicated and very hard to fix.
Inline six engines are more reliable and cheaper to create for manufacturers
Not only is the straight-six engine better in all the regards mentioned above, but the real reason why most car manufacturers have switched or are switching to it instead of the V6 is that it is cheaper to produce.
The most cost-effective approach is always sought in big companies. BMW has been producing not only inline-six engines but also inline-four, as well as inline-three engines. The bore-spacing in all those options has been the same. (This is the space between two cylinders in the engine).
One of the main concerns of using straight engines was that they are taller than V6s and pedestrians being hit might end up hurt in a more dangerous way due to the hard head of the engine. But this has been battled with technology and driver assisting features as well as safety improvements like automated emergency braking for the sake of pedestrians.
Which BMWs have inline-six engines?
There have been more than 22 produced inline-six BMW engine models from 1993 until 2020. More than any other type of engine, produced by BMW. That alone speaks for the engine. It is one of the founding pillars of BMW’s success and sheer driving pleasure.
Typically, the straight-six engine is abbreviated with l6 or L6 and is found in most famous BMW models, aside from the high-end luxury BMWs that use complex and expensive V8 or V12 engines. BMWs with inline-six engines include:
- BMW M3 E46
- BMW N55
- BMW 3 Series
- BMW 5 Series
- BMW 6 Series
- BMW 7 Series diesel cars – 730d, 740d
- BMW S54
- BMW 1 Series
- BMW X5
- BMW X6
- BMW X4
To limit the list, we would say that BMW has used a straight-six engine across all its Series going all the way from the BMW 1 Series to the BMW 7 Series, as well as in its X – luxury crossover SUVs like the BMW X3, X5, or X7.
It is safe to say that the engine is extremely versatile and very reliable, compared to the traditional V6 engine that car manufacturers like Audi produce. It has been an essential part of BMW’s success over the years.
Are there any common issues with inline BMW engines?
The most common inline-six engines like a BMW N52, which is used in the 528i and in the 328i are:
- Water pump failure and displacement
- VANOS failures
- Hydraulic adjusters
- Cover leaks of the valve
- Housing gasket leaks
- Slower start-up
Of course, these are just a few possible issues that can arise in any engine. VANOS failure usually can be seen in over 70,000 miles on your vehicle, and the others are typically experienced way over that amount.
FAQ
Are BMW straight-six engines reliable?
One of the most important reasons why BMW uses inline-six engines is that they are more reliable than a standard V6 engine. Some of these engines have been reported to run for over 200k miles. Of course, that greatly depends on how it has been maintained and driven throughout the lifespan of the vehicle.
What types of engines does BMW produce?
BMW is most well-known for producing inline or straight-six engines. As well as V8, V10 and V12 engines. BMW has never produced and used a V6 engine, mainly because it is not a good fit for rear-drive cars due to its size and shape. Aside from these, BMW has also produced inline-four and inline-three engines, used in some smaller cars. Moreover, it also produces electrical engines for its hybrid vehicles.
Does BMW produce Rolls-Royce engines?
Yes, BMW produces the V12 engines used in Rolls-Royce, as it actually owns the company. It produces around 3000 Rolls-Royce engines per year. Rolls-Royce Phantom, for example, uses a 6.8 L V12 naturally-aspirated engine, whereas the Ghost or Wraith, use a 6.6 L twin-turbo engine.