Article Summary
- The BMW G60 5 Series is due for a mid-cycle facelift around 2027, and rumors suggest the 520d variant could be upgraded from its current four-cylinder B47 to the straight-six B57 diesel.
- The B57 is already used in the 540d and produces up to 286 hp and 700 Nm of torque, with a 48-volt mild-hybrid system — making it one of the most refined and powerful diesel engines on the market.
- The move would signal that BMW has no intention of abandoning diesel, particularly in key European markets where oil-burners still dominate executive sedan sales.
We’ve been hearing whispers from lately that BMW is far from done with their diesel engines and the latest rumor, adds more substance behind these assumptions. According to sources, the upcoming G60 5 Series facelift — already spotted in early spy photos testing ahead of a suspected 2027 reveal — could bring something unexpected to the 520d nameplate: a straight-six diesel under the hood.
Yes, you read that right. Sources suggest BMW may be considering dropping the B57 3.0-liter inline-six diesel into the facelifted 520d, a move that would represent a significant upgrade from the current four-cylinder B47 unit that powers today’s base diesel 5 Series.
Why the B57 Is Worth Getting Excited About
If you’re not familiar with the B57, allow us to make the introduction. This 3.0-liter, twin-turbocharged inline-six is one of the finest diesel engines ever built — full stop. In its various states of tune, it produces between 286 hp and 340 hp, with torque figures that will make your neck snap: up to 700 Nm (516 lb-ft) in standard 40d guise, and as high as 760 Nm in its more extreme applications. In the 540d xDrive, it rockets the 5 Series from 0 to 100 km/h in around 4.6 seconds — numbers that would have been considered sports car territory not long ago.
The B57 also benefits from a 48-volt mild-hybrid system in newer applications, adding a belt-integrated starter-generator that recovers energy under braking and provides an additional electric boost when needed. It’s a diesel that genuinely doesn’t feel like one — smooth, linear, and almost eerily quiet at highway speeds.
Why the Powerful Diesel in the 520d?
The 520d has always been the volume seller in the 5 Series diesel lineup — the rational choice, the company car staple, the long-haul executive’s trusted companion. Giving it a six-cylinder could blur the line between it and the 540d, but it would also send a very clear message: BMW is not walking away from diesel. At the same time, we expect the 520d to make less power than the 540d to not step on its toes.
It’s also refreshing that at a time when many European automakers have been quietly shelving their oil-burners, BMW has continued to invest in diesel technology. The 540d remains one of the brand’s best-kept secrets, and reports suggest that diesel still accounts for a substantial share of 5 Series sales in key markets like Germany, the UK, and across Eastern Europe. Bringing the B57 downstream into the 520d — even in a detuned 286 hp variant — would be a bold statement of intent.
Take It With a Pinch of Salt — For Now
As always with rumors at this stage, nothing is confirmed. BMW has not officially announced any powertrain details for the G60 LCI, and the facelift itself is still at least a year away from showrooms. But the timing makes sense: the B57 is a mature, proven, and already homologated unit, and adding it to a refreshed 520d would require relatively modest re-engineering effort.
If it happens, diesel loyalists will have reason to celebrate. And if BMW really does slot the B57 into the 520d facelift, consider it one of the most compelling sleeper sedans on the market. It’s a smart decision for buyers who still want diesels, at an affordable price, especially for a midsize car.
