BMW B47 Engine Reliability Guide
The B47 is BMW's 2.0-litre four-cylinder diesel that replaced the N47 in 2014 and is still in production today. It's the engine you'll find in most recent used 318d/320d/520d/X1/X3 diesels and, crucially, it is ULEZ-compliant (Euro 6). The big thing to verify on any used example is whether the EGR-cooler fire-risk recall (NSC R/2018/151) has been completed.
Quick verdict
The B47 is a sensible buy for UK diesel users who need ULEZ compliance. Significantly more reliable than the N47 it replaces, the timing-chain issue is largely resolved on post-2017 builds. With the EGR recall completed and documented servicing, 200,000+ miles is realistic. Verify the recall paperwork before parting with money.
What is the BMW B47?
Most B47 cars in UK classifieds are 2017+ F-series and G-series models , high proportion of ex-company-car stock with fleet service history. That's good (regular services) and bad (relentless motorway miles, some with questionable cold-start care). AdBlue/SCR glitches are the second-most-common buyer concern after the recall. If the recall is outstanding, it's free work at any BMW dealer, book it before you collect.
| Full engine code | B47D20 |
|---|---|
| Configuration | I4 turbo diesel, common-rail, aluminium block |
| Production years | 2014-present |
| Applicable chassis | F20, F21, F22, F23, F30, F31, F32, F33, F34, F36, F10, F11, F48, F39, F25, G20, G21, G22, G23, G26, G30, G31, G60, G61, G01, G02, G05, U11 |
| Badge names | 116d, 118d, 120d, 218d, 220d, 318d, 320d, 418d, 420d, 520d, X1 18d, X1 20d, X2 20d, X3 20d, X4 20d, X5 25d |
| Real-world UK MPG | 48 to 58 mpg combined, 55 to 65 mpg motorway |
| Emissions / ULEZ | Euro 6, ULEZ-compliant |
| Successor | n/a |
| Reliability score | 6 / 10 (Bimmer.AI internal) |
Common problems
Every failure mode below is based on UK DVSA/recall data, BMW press archives, and observed patterns across independent specialist maintenance schedules. Cost ranges are indicative UK figures.
| Failure mode | Severity | Frequency | Typical onset | UK repair range |
|---|---|---|---|---|
| EGR cooler fire-risk recall (NSC R/2018/151) | Serious | Very common | 40 to 150k mi | Free (recall) or up to £1,100 |
| Timing chain (early B47, 2014-2016) | Moderate | Uncommon | 80 to 140k mi | £1,500 to £2,500 |
| DPF regen failure | Moderate | Common | 50 to 120k mi | £400 to £1,500 |
| AdBlue / SCR system fault | Moderate | Common | 40 to 100k mi | £300 to £1,200 |
| Swirl flap failure (carried over from N47/M47) | Catastrophic | Uncommon | 100 to 180k mi | £200 to £400 |
EGR cooler fire-risk recall (NSC R/2018/151)
- Unexplained coolant loss
- White smoke from exhaust when warm
- Sweet smell from exhaust
- In rare cases: smoke from engine bay or ignition fire
What to do about it: CHECK RECALL STATUS at gov.uk/check-vehicle-recall using the VIN. BMW completed the remedy free of charge on most affected cars. If outstanding, book at any BMW dealer.
If ignored: Engine fire (rare but documented) or hydrolocked engine. £4,000+ replacement.
UK repair exposure: Up to £1,100 (free under recall if applicable).
Recall / TSB: DVSA recall NSC R/2018/151 covers ~320,000 UK vehicles with N47/B47 engines.
Additional notes: If a used car claims 'recall completed', insist on dealer paperwork.
Timing chain (early B47, 2014-2016)
- Mild rattle on cold start
- P0016/P0017 cam-crank correlation codes
What to do about it: Listen on cold start during viewing. Post-2017 rarely affected.
If ignored: Engine destruction.
UK repair exposure: £1,500 to £2,500.
Additional notes: Significantly less common than on N47.
DPF regen failure
- DPF warning light
- Limp mode
- Failed MOT on emissions
What to do about it: Motorway driving 30+ min weekly. Avoid school-run-only use.
If ignored: Cracked DPF: £1,500-£2,500 to replace.
UK repair exposure: £400 to £1,500.
AdBlue / SCR system fault
- 'X miles to restricted start' warning
- AdBlue level / quality warning
- NOx sensor warning light
What to do about it: Sealed AdBlue only. Top up promptly.
If ignored: Refusal to start (EU regulation, not a fault).
UK repair exposure: £300 to £1,200.
Additional notes: NOx sensor £300-500. SCR pump £600-1,200.
Swirl flap failure (carried over from N47/M47)
- Sudden power loss
- Misfire / rough running
What to do about it: Indie can blank-plate the flaps preventatively, £200-400.
If ignored: Ingested flap → bent valves → £4,000+ engine work.
UK repair exposure: £200 to £400.
Additional notes: Less common than on N47.
Preventative maintenance schedule
UK independent specialist consensus, typically more cautious than BMW's factory service intervals, especially around oil and timing components.
| Task | Interval | Typical cost | Fix |
|---|---|---|---|
| Engine oil + filter (BMW LL-04) Independent specialist consensus. | Every 10,000 mi | £90 to £140 | DIY |
| Fuel filter | Every 30,000 mi | £60 to £110 | DIY |
| Air filter | Every 30,000 mi | £25 to £50 | DIY |
| AdBlue top-up Sealed AdBlue only. | Every 10,000 mi | £15 to £30 | DIY |
| Coolant | Every 60,000 mi | £120 to £180 | Specialist |
| Brake fluid | Every 24,000 mi | £60 to £100 | Specialist |
| DPF forced regen / cleaning | Every 60,000 mi | £80 to £250 | Specialist |
| EGR recall verification (NSC R/2018/151) FREE at any BMW dealer. | ASAP | Free | Specialist |
Long-term verdict
Significantly more reliable than the N47 it replaces. The timing chain issue is largely resolved on post-2017 builds. The remaining concern is the EGR cooler fire-risk recall (NSC R/2018/151), verify it has been completed on any used purchase. With that done and a documented service history, a well-maintained B47 can realistically do 200,000+ miles. A sensible buy for UK diesel users who need ULEZ compliance.
Buy, negotiate, or walk away
Buy
Post-2017 build, EGR recall completed with BMW paperwork, full service history (BMW or known indie), AdBlue warnings not currently present, no cold-start rattle, chain quiet.
Negotiate
EGR recall outstanding (book it, it's free, but factor in collection/return trip). Active AdBlue warnings (£300-£1,200 depending on NOx sensor vs SCR pump). 2014-2016 early B47 with no chain receipts past 100k.
Walk away
Cold-start rattle lasting more than a couple of seconds on an early B47. Swirl-flap debris on borescope. No service history at 100k+ miles. Persistent limp mode despite recent diagnostic work.
Check a specific B47 listing
Paste any BMW B47 listing, VIN, or registration. Bimmer.AI returns a B47-specific buyer report in 30 seconds.
Run a Bimmer.AI buyer report →Bimmer.AI is designed to help you identify BMW-specific buyer risks before you travel, negotiate, or pay for an inspection. It does not replace a physical inspection by a qualified mechanic, a legal vehicle-history check (e.g. HPI Check), or independent verification of finance, stolen, or write-off status. Repair-cost ranges are indicative UK figures that vary by region, specialist, parts supply, and labour rates.
Frequently asked questions
Is the BMW B47 engine reliable?
Yes, significantly more reliable than the N47 it replaced. The timing-chain issue is largely resolved on post-2017 builds, and the engine is Euro 6 ULEZ-compliant. The main buyer concern is verifying the EGR-cooler fire-risk recall (NSC R/2018/151) has been completed.
What is the EGR recall NSC R/2018/151 on the B47?
DVSA safety recall covering ~320,000 UK BMWs with N47 and B47 diesels. The EGR cooler could leak coolant into the intake and, in rare cases, cause a fire. BMW completed the remedy free of charge on most affected cars. Check status at gov.uk/check-vehicle-recall using the VIN before you buy.
Is the B47 ULEZ-compliant?
Yes. The B47 is a Euro 6 diesel and is exempt from London's ULEZ charge. This is a meaningful difference vs the N47 (Euro 5, not ULEZ-compliant) and a common reason buyers move from N47 to B47.
Is the B47 prone to the same timing-chain problem as the N47?
Much less so. Early B47s (2014-2016) still had occasional chain stretch, but post-2017 builds are rarely affected. Listen on a cold start during the viewing, any rattle warrants investigation.
How much is AdBlue / SCR repair on a B47?
NOx sensors run £300-£500 fitted; an SCR pump replacement is £600-£1,200. AdBlue quality warnings are usually resolved by a sealed-bottle top-up (£15-£30). If the dashboard is showing a restricted-start warning, resolve before purchase, EU regs prevent the car from starting once the countdown expires.
Which BMWs use the B47 engine?
Most current UK diesels: 118d/120d (F20/F40), 318d/320d (F30/G20), 520d (F10/G30/G60), X1 18d/20d (F48/U11), X3 20d (F25/G01), X4 20d, plus X5 25d variants. Always verify chassis + engine, not just the badge.