The B47 is one of BMW's most reliable modern diesel engines. Based on 930 real UK replacement enquiries in 2025, it shows a lower failure rate than its predecessor, the N47, with most issues appearing after 100,000 miles.
The BMW B47 is a significantly more reliable engine than the N47 it replaced. In our 2025 dataset, the B47 generated just 930 replacement enquiries compared to 1,450 for the N47, despite its popularity across the 3-Series, 5-Series and X3.
Read the full data breakdown, including mileage distribution, common failure modes and what this means for owners, below.
How does the B47 compare to other BMW engines in our 2025 enquiry data?
The B47 is BMW's 2.0-litre four-cylinder turbo-diesel, introduced in 2014 as the successor to the N47. In our 2025 UK data, it generated 930 replacement enquiries [EM-VERIFIED], placing it 6th on our list of BMW engines by request volume. This is significantly lower than the N47 (1,450 enquiries) and also lower than the N57 (830) and B58 (540).
However, request volume alone doesn't tell the whole story. The B47 is also fitted to a very large number of vehicles — it's one of BMW's most common engines across the 3-Series, 5-Series, X1, X3 and X4. When you consider the B47's enquiry volume against its market share, it becomes clear that it is genuinely more reliable than the N47, with a lower proportion of vehicles needing a replacement engine.
| Engine | 2025 Enquiries | Typical Host Value | Recon Supply Cost | R-to-V Flag |
|---|---|---|---|---|
| N47 | 1,450 | £3,000–£9,000 | £3,200–£5,500 | ⚠️ Watch |
| B47 | 930 | £7,000–£20,000 | £2,800–£4,500 | ✅ Safe |
| N57 | 830 | £8,000–£25,000 | £4,500–£7,000 | ✅ Safe |
| B58 | 540 | £15,000–£45,000 | £3,800–£6,000 | ✅ Safe |
All enquiry figures [EM-VERIFIED]. Cost and value bands [EM-QUOTE / THIRD-PARTY].
B47 failures typically occur after 100,000 miles, with a noticeable peak around the 120,000-mile mark.
Mileage distribution [EM-INTERVIEW / PATTERN DATA]. Actual mileage can vary depending on service history and driving style.
The B47 is a robust engine, but it has a few common weak points. Here are the most frequent failure modes we see in the data.
| Failure Mode | Likelihood | Typical Mileage | Typical Cost | Severity |
|---|---|---|---|---|
| EGR Cooler Failure | High | 80k–120k | £600–£1,200 | Monitor |
| EGR Cooler Recall | High (Recall) | 60k–100k | FOC (Recall) | Monitor |
| Timing Chain Wear | Medium | 100k–150k | £1,500–£2,500 | Monitor |
| AdBlue System Issues | Medium | 60k–120k | £500–£1,500 | Monitor |
| DPF Blockage (Urban) | Medium | 80k–150k | £400–£1,200 | Monitor |
Data sources: [EM-INTERVIEW / THIRD-PARTY]. Severity: Low · Monitor · Immediate · Catastrophic.
With proper maintenance, a B47 can exceed 200,000 miles.
The B47 is considered a long-lived diesel engine. Most failures occur between 100,000 and 150,000 miles, with many examples exceeding 200,000 miles without major issues. The key to a long B47 life is regular maintenance, particularly oil changes at the correct intervals (around 18,000 miles or 2 years, whichever is sooner).
Our data suggests that the B47's predecessor, the N47, had a shorter average lifespan, with many failures occurring below 100,000 miles. The B47's improved design, including a front-mounted timing chain (unlike the N47's rear-mounted chain), makes it both more durable and easier to service.
Average lifespan: 180,000–220,000 miles with good maintenance [PATTERN DATA].
The B47 is a reliable, safe diesel engine. It has significantly fewer issues than its predecessor, the N47, and its replacement cost is well within the value of most BMWs it powers. The main concerns — EGR cooler failures and AdBlue system issues — are common across all modern diesels and are not specific to the B47. BMW's recall on the EGR cooler has also addressed one of the most frequent failure modes.
If you're considering a BMW with a B47 engine, we would recommend it. Regular maintenance and attention to the EGR cooler and AdBlue system will ensure a long, trouble-free life. This engine is a safe buy for most owners.
In our 2025 data, the B47 generated 930 replacement enquiries, compared to 1,450 for the N47. This indicates a significantly lower failure rate, making the B47 one of BMW's most reliable diesel engines. The typical failure mileage is around 120,000 miles.
Yes, the B47 is considerably more reliable than the N47. The B47 has a front-mounted timing chain, whereas the N47's rear-mounted chain was a known weak point. The B47 also has fewer reported cases of catastrophic failure and is generally considered a more robust design.
The most common B47 failures are EGR cooler failure, timing chain wear (less common than N47), AdBlue system issues and DPF clogging in urban use. Most of these are manageable and not catastrophic, particularly compared to the N47's timing chain issues.
With proper maintenance, a B47 can last 180,000–220,000 miles. Many examples exceed 200,000 miles without major engine work. Regular oil changes and attention to the EGR and AdBlue systems are key to maximising lifespan.
No, the B47 is a safe and reliable engine. It is one of BMW's best modern diesels. If you're looking at a B47-powered BMW (e.g., 320d, 520d, X3 20d), we would recommend it, particularly if the vehicle has a full service history.
930 Real EnquiriesThe full B47-specific dataset from 2025 UK enquiries.
Independent DataBuilt from real specialist quotes and market data.
Expert-VerifiedCross-referenced with 100+ UK engine specialists.
100% IndependentNo manufacturer influence or sponsors.
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