Introduction
The BMW 5 Series G30 has been in production since 2017—it’s the seventh generation of the midsize luxury sedan. The 520d version uses the 2.0-liter B47: a four-cylinder turbo diesel. It’s popular with buyers who want a balance of performance, efficiency, and comfort. The interior is nicely finished, the ride is compliant, and the tech suite is current.
The big question for owners and shoppers is how the B47 holds up at high mileage. Below is a rundown of the design, the typical problems, the service schedule, and real-world owner experience.
Specifications
| Parameter | Value |
|---|---|
| Engine | B47, 2.0L, 4 cylinders, turbo diesel |
| Power | 190 hp (140 kW) at 4,000 rpm |
| Torque | 295 lb-ft from 1,750 to 2,500 rpm |
| Transmission | 8-speed ZF 8HP automatic; 6-speed manual (market dependent) |
| Drivetrain | sDrive (rear-wheel drive) or xDrive (all-wheel drive) |
| 0–60 mph | ≈ 7.5 s |
| Top speed | 146 mph |
| Rated fuel economy | 47–52 mpg (combined) |
| Emissions standard | Euro 6; Euro 6d-temp for later versions |
Those numbers define the character of the car: torque is there from 1,750 rpm, so the 520d pulls confidently around town without revving. A 7.5-second run to 60 mph and a 146-mph top speed are typical figures for a diesel midsize luxury sedan.
B47 Engine: Design
The B47 is the successor to the N47: a 2.0-liter four-cylinder turbo diesel with common-rail injection, a variable-geometry turbocharger, and sophisticated engine management. Ignition is by compression.
The headline engineering change over its predecessor is the reworked timing chain. On the N47, that chain was the weak point—the cause of the failures. BMW redesigned it for the B47, and the tendency to snap dropped. That difference is the whole reason the engine was developed anew.
Transmission and Drivetrain
Torque flows through an 8-speed ZF 8HP automatic or a 6-speed manual. The manual isn’t offered in every market: a large share of markets get the G30 520d with the automatic only. Drive is rear-wheel (sDrive) or all-wheel (xDrive).
Fuel Economy
The rated combined figure is 47–52 mpg, and it moves with driving conditions. Real-world mixed driving is thirstier than the spec—owners see roughly 37–46 mpg.
Reliability at High Mileage
Owners report more than 124,000 miles without major failures—provided maintenance stays on schedule. Individual reviews mention 62,000 miles with the engine still in good condition. Forum threads describe cars that “never missed a beat” over two years of ownership, with much of that mileage on the highway.
The spread in these numbers comes from mixed units in the source data—more on that below, in the contradictions section.
Common Problems
- Electric water pump. A known weak spot. Failure causes engine overheating. Preventive replacement is recommended after 62,000–81,000 miles.
- High oil consumption. Some owners report elevated oil use. Regular level checks and the correct oil grade are essential.
- EGR and DPF coking. Short trips foul the EGR valve and the diesel particulate filter (DPF). Regular highway runs burn off soot and prevent clogging.
- Timing chain. The B47 fixed the N47’s problem, but the chain remains a component to monitor. Stretching does show up at high mileage—just far less often than on its predecessor.
- AdBlue system. Euro 6d-temp and newer versions use urea injection. Regular maintenance and quality fluid keep it trouble-free.
Service Schedule and Preventive Maintenance
- Oil change every 9,000–12,000 miles or once a year, whichever comes first.
- Oil meeting the BMW Longlife-04 specification.
- Timing chain and guide inspection around 99,000 miles—roughly the same milestone as the water pump.
- DPF regeneration: an occasional 20–30 minute run at highway speed.
- EGR valve cleaning or replacement if the idle turns rough or power drops.
- Coolant replacement and a cooling-system check for leaks.
- Regular checks of the oil, coolant, and AdBlue levels.
Owner Reviews
YouTube reviews of the B47 agree on one thing: it’s “a very easy engine to service and repair.” One creator flat-out recommends the motor as reliable, especially next to other makers’ powertrains. On the BMW Fanatics forum, an owner notes that the B47 proved dependable in his mother’s 320d, and that the car is relatively easy to work on. DIY enthusiasts value how accessible the components are.
Negatives are rare. In a Facebook group, one member argued the engine is “worse” and servicing is “expensive.” It’s an isolated comment, though: most owners report a positive experience.
Against the Competition
Against the N47, the B47 wins on the timing chain, and on fuel economy and emissions. Against the Mercedes-Benz OM654: the Mercedes holds a slight edge in smoothness and refinement, but the B47 answers with performance and the overall package. The Audi 2.0 TDI is a strong rival, yet buyers more often pick the B47 for its character and handling.
Cost of Ownership
Fuel is the biggest line item, but the 520d is frugal, especially on the highway. Insurance for a premium midsize luxury sedan is moderate and depends on your region and driver profile. Dealer service is expensive; independent shops that know BMW charge less without a quality penalty. A major service costs substantially more than a minor one. Genuine (OE) parts are pricey, but decent aftermarket alternatives exist; consumables such as brakes and tires cost about the same as on other premium cars. With a full service history, a 520d holds its value well.
Buyer and Owner Checklist
- Stick to the service schedule: oil, filters, inspections.
- Fit OEM or quality aftermarket parts instead of cheap no-name components.
- Check oil, coolant, and AdBlue levels regularly.
- Drive the car regularly: if your trips are short, take one highway run a week so the DPF doesn’t clog.
- React to warning lights immediately—early diagnosis prevents expensive repairs.
- Buying used: demand a full service history and a pre-purchase inspection by a trusted mechanic.
- For a used 520d, consider an extended warranty.
Contradictions in the Source Data
- One quote mixes units: “over 200,000” and “100,000” in the same source—it’s unclear whether miles or kilometers were meant (they convert to roughly 124,000 and 62,000 miles).
- The rated combined economy of 47–52 mpg doesn’t square with the claimed real-world figure—the ranges overlap, which points to duplication.
- The overall reliability section claims owner reviews are “consistently” positive, then immediately cites a negative review calling servicing “expensive and poor” and dismisses it as isolated without supporting data.
- The spec table lists Euro 6, while the AdBlue section mentions Euro 6d-temp and newer without years or markets—it’s unclear which versions each statement applies to.
- The manual is listed as “market dependent,” but no specific markets are named; a large share of markets supply the G30 520d with the automatic only.
The Bottom Line
The G30 520d with the B47 is a predictable choice in the premium diesel segment: torque from low revs, frugality, and a timing chain far less prone to snapping than the N47’s. The weak spots are specific—the electric water pump, EGR/DPF fouling in city use, and chain checks at high mileage. Shop for a car with a full service history, and book an independent inspection before you buy.