If a simpler, less expensive-to-maintain all-electric vehicle like the Tesla Model 3 Long Range isn’t in your driveway for at least the next five years, then pretty much any BMW with the 3.0-liter B58 six-cylinder engine will do just fine. That engine is incredibly smooth, powerful, and efficient. But you might want to be a little cautious with its latest iteration. Here’s why.
I recently recommended the X5 xDrive40i, X5 xDrive50e and M340i to a couple of acquaintances and friends. I also just explained in another article why the X7 xDrive40i (with some options) is the best three-row family car Off-road that people living in North America can purchase today.
I have nothing to gain from these recommendations and statements. I do not ask the Bavarian car brand for press, nor do I receive any compensation from the company or its dealers. Furthermore, I do not own any car stock.
A family friend ended up ordering a rear-wheel drive Tesla Model 3 Long Range after I explained to him why a Electric vehicle would suit his mobility needs much better than the Mercedes-Benz C-Class he was eyeing. So, I'm not even a BMW fanboy.
I just wanted to get all of this out of the way before I start looking into what problems the new B58 engine might have. Spoiler alert: I blame the European Union (EU) and the United States Department of Transportation (USDOT) for what's going on.
Photo: BMW
Truly a jewel
Soon after the B58 made its official debut, tuners discovered that it had great potential to produce even more power. All they had to do was replace the high-pressure fuel pump (HPFP) and add a new, less restrictive downpipe for improved airflow. In some cases, these two upgrades nearly doubled the powerplant’s peak horsepower. Cost-wise, it wouldn’t have cost you more than $5,000.
The first generation B58 proved that BMW had great engineers and was able to learn from past experiments. After all, the new six-cylinder was derived from the N54 and N55 engines. These two were not exactly known for being extremely reliable or flexible.
However, engineers did find some complaints about the early B58 units. They didn’t like that the timing chains and oil pump were located so close to the flywheel. BMW did this to balance out harmonics and reduce timing chain replacements. If you know someone with a post-2015 BMW that has a six-cylinder under the hood, chances are they’ve never had any issues with those parts.
But progress changes things and also increases costs. Nowadays, it is no longer so economical or convenient to apply a simple tune-up and run BMW's most well-known and appreciated engine with more horsepower than the manufacturer intended.
The Bavarians also took some questionable steps to ensure that tuners would no longer have an easy life. The electronic control unit (electronic control unit), also known as the brains of a vehicle's engine, has been locked down for security, component protection, warranty, and most importantly, intellectual property protection. However, most of them are capable of cracking the code and updating the powertrain.
Photo: BMW
The intellectual property part is even more important than you might think. BMW isn’t necessarily afraid of competitors stealing its design. It already has corporate clients for that. Just look at Morgan or Ineos. The mechanical beating heart was so good that it even caught the attention of Toyota. The Japanese brand is known for prioritizing reliability and simplicity and even partnered with BMW to introduce the B58B30M1 version of the engine, which was installed in the 2020 Supra GR. Other vehicles that came with that engine were the 2020 X5, X7, Z4, and 7 Series models.
Toyota took its time getting close to BMW and working with the Bavarians. The B58 debuted in 2015, when it was installed on the facelifted F30 3 Series. But once they got involved, the project became even easier. Most mechanics are happy to work on recent versions of the B58.
However, it is worth noting that BMW and Toyota failed to anticipate a problem with the positive crankcase ventilation (PCV) valve. It doesn’t seem like a major part, but it has led to turbo failures on some models. Late last year, the Bavarians decided to extend the warranty on that part to 15 years or 150,000 miles in an effort to fix the component at their own expense.
Fortunately, BMW recognized the problem and took significant steps to fix it or make sure owners didn’t have to deal with it out of pocket. That specific problem probably affected a small batch of engines.
Photo: BMW
Fingers crossed, maybe the excessive coolant consumption, VANOS solenoid O-ring, valve cover gasket and oil filter issues have also been resolved.
Novelty and forced efficiency
The latest versions of the six-cylinder are the B58TU2 and the B58B30M2. The latter is present on BMW units with the 40i designation or, in the case of the X3, with the M50 moniker. It is too new to decide whether it is reliable or not. The former, however, has been around for over two years. It is the version that interests us. It made its debut in the facelifted X7.
An experienced BMW enthusiast who knows how to properly modify BMWs for more power and to keep up with all the latest developments recently said that the new cylinder deactivation system does not work properly, which leads to damage to the rocker arm. The rocker arm is a valvetrain component that sits between the pushrod, intake, and exhaust valves. It transfers the pushrod's motion to the valve. When it does not work as intended, it can prevent the valves from opening and closing properly.
He also said that the valve springs may pop out of position or break on some units, but that's based solely on personal observations. Doesn't mean it's a widespread problem.
Cylinder deactivation on a straight-six doesn’t seem like a good idea, but pair it with hybridization and you could have a recipe for beating tougher emissions standards. Manufacturers are forced to make their engines as efficient and clean as possible. Otherwise, they risk paying hefty fines.
However, it’s worth noting that this guy is testing the limits of these engines. His findings may not point to reliability issues that could affect thousands of Gen 3 B58 BMW buyers. But what this guy is saying could help you take better care of your six-cylinder BMW. You can stay ahead of the curve by knowing what’s what. Below, you can find his detailed explanations and answers to some important questions.
Ultimately, don't be discouraged. All engines can be iffy. I, for one, trust BMW. The brand wouldn't risk ruining its most popular engine. If there are real problems, they will probably be fixed.
