Since 2015, the BMW B58 motor has been one of the most revered tuning platforms in new cars. As the successor to the potent N55, the B58 retains a lot of what made the N54 and N55 such great engines, while being updated with higher stock boost pressure, increased displacement, and an increase in compression ratio.
First seen in the 2016 340i, the B58 gained a reputation for being an engine full of tuning potential and solid reliability.
The B58 has now seen its fair share of use in models like the 340i, 440i, M340i, X4 M40i, and even the newest generation of the Toyota Supra, among many others. The consensus is that the B58 holds its own in terms of reliability, even compared to its Japanese and American counterparts.
Not all B58s are created equal. The largest change came in 2019 with the release of the B58TU1. The TU1 refresh introduced changes such as a revised timing chain, fuel system, cylinder heads, and other small updates.
The TU1 sees a slight bump in power over the original. BMW introduced the refresh with emissions in mind, so many of the changes are intended to improve the fuel economy due to the EU’s emissions crackdown.
Being such a new platform, the TU1 doesn’t have much of a track record in terms of reliability yet, but one could assume that BMW’s changes could only mean better reliability compared to earlier models as they had a chance to button up some known issues.
With that being said, some of these common issues could very well apply to the TU1 as well, so owners and prospective buyers should still keep an eye out for them.
VANOS is BMW’s proprietary system for dynamic valve timing, similar to the well-known Honda VTEC or Toyota’s VVT-i. With VANOS specifically, the timing is controlled by changes in oil pressure, which are prompted by a tightly wrapped coil called a solenoid. A repeat offender on many BMW motors, the VANOS solenoid plagues B58 owners as well.
The most common cause of VANOS problems in the B58 (and many other BMW motors) is a failure of the solenoid’s o-ring. With time, the rubber o-ring degrades due to wear and high temperatures. This failure allows oil to seep through and disrupt the ability to actuate the VANOS solenoid..
In other cases, the solenoid can become clogged with contaminants from the oil. Dirt, metal shavings, and old oil can cause the solenoid to be unable to function properly.
Both of these problems usually cause similar symptoms. Loss of power, sluggish throttle response, decreased efficiency, limp mode, and a rough idle are just a few issues that can arise as a result of VANOS issues.
Since you can’t see VANOS failure coming, the only true way to prevent it is proactive maintenance. BMW recommends the replacement of the VANOS seals every 50,000 miles and even a complete replacement of the system at 70,000 miles.
Another mainstay in the BMW “common problems” category is the valve cover gasket (VCG). This isn’t unique to BMWs per se, since any modern car is going to come with a rubber VCG that degrades with use.
However, BMW VCGs seem to have a knack for failing. Between 60,000-100,000 miles, owners should be vigilant of leaks around that area, as oil loss can cause major headaches if left untreated.
Keep an eye out for symptoms such as the smell of burning oil, soaked spark plugs, a low-oil light, and visible leakage by the gasket.
It’s not like BMW has turned a blind eye to this after their previous models though. One of the main causes of wear on rubber gaskets is the extreme heat cycles experienced by the engine. The transition from cold to hot, and vice versa, repeatedly is the main source of engine wear in general.
The B58 is BMW’s attempt to remedy the issue. The heat retention system on the B58 is claimed to retain engine temperature for up to 36 hours, allowing a more gradual heat cycle process and less temperature shock for sensitive parts such as the VCG.
“Disintegration” is not a word you want to hear in most situations when talking about a car.
It’s simply the best way to describe this issue though. The B58 (and other BMW motors for that matter) come with an odd habit of having their oil filters ripped to pieces from normal use.
As oil passes through, the filter eventually starts to pull away from the housing and eventually rip into multiple pieces.
Oil filters, even those made by BMW, are not expensive. That’s not necessarily the issue at hand here though. The oil filter can’t do its job if it’s not intact, so this allows a path for foreign particles and contaminants to reach places they’re not supposed to be.
These particles of metal, dirt, etc, can cause rapid corrosion in the engine and eventually expensive issues down the line.
The issue is best avoided with proper oil and filter change intervals. Not going over the recommended interval is important anyways, but it also gives less of an opportunity for wear and tear to rip the filter up.
In a perfect world, engines are designed and assembled so precisely that fluid loss is essentially eliminated. In the real world though, engines have flaws. Coolant can leak out or burn off in certain areas of an engine, but usually at a slow rate that doesn’t cause much of an issue.
Then there’s the B58. While there hasn’t been a specific cause pinpointed, many B58 owners report a faster-than-usual loss of coolant, even on lower mileage motors. Some have attributed it to faulty coolant tank caps, or seals around the cooling system.
In the end, slight coolant loss isn’t something to panic about. As long as you’re topping it off when you need to, there’s not much you need to do. It’s just something all B58 owners should be aware of, especially those that don’t poke around under the hood too much, as it can be easy to miss when not looking for it.
If you do fail to top off the coolant, however, the car can begin to overheat. In serious cases, this can cause catastrophic damage to the engine.
Due to this seeming to be a small factory flaw or just expected coolant loss, there isn’t much to be done in the way of prevention. Checking your seals and coolant cap is always recommended though, as any visible leaks can mean much worse for your vehicle than the gradual loss of coolant.
No engine is perfect. Despite the improvement in reliability over its older brothers, the B58 still has some common issues that you should know if you own or are looking to purchase a B58-powered car.
If you want to compare it apples-to-apples with other motors though, the B58 holds its own as a solid platform that will run for a long time with proper maintenance. In terms of Euro cars, there might not be a platform as tuner-ready yet daily-drivable as the B58.
If you’re looking for a platform ripe for some bolt-ons and a tune, while also managing to keep its composure with increased boost and hard driving, the B58 might be a good choice.
Any motor, German or not, can and will have flaws. The B58 has a few issues that have been present in BMW engines for a few generations, so the causes, symptoms, and fixes are well-documented and readily available.
Most of these problems can be prevented with a little foresight and a small investment in preventative maintenance. While seemingly pricey upfront (it’s still a Bimmer), being proactive can save you thousands in the future.
If you own a B58-powered car, trust your maintenance to Alex’s Autohaus in Midvale, Utah. Our European motor specialists have seen it all, and know how to service engines as special as the B58 with the highest quality.
Call or schedule an appointment online today to secure your spot with the premier Euro service center in the Salt Lake Valley!
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