BMW N47 Engine Reliability Guide
The BMW N47 is the 2.0-litre four-cylinder diesel that powered most three-series and five-series BMWs between 2007 and 2014. It's economical, plentiful in the used market, and — if you buy carelessly — potentially a £1,500–£2,500 timing-chain bill waiting to happen. This guide tells you exactly what to check before buying one in the UK.
Quick verdict
The N47 can be a good used diesel engine, but timing-chain risk dominates every buyer decision. With documented chain replacement and a clean service history it can realistically do 250,000+ miles. Without it — especially on pre-2011 builds where the chain is at the rear of the engine — treat the car as a £1,500–£2,500 liability and negotiate, or walk away.
What is the BMW N47?
Most N47 cars you'll see in UK classifieds are 2010–2014 F-series or late-E90 3 Series and F10 5 Series. Nearly all of them are out of warranty, and BMW UK has declined goodwill on almost every out-of-warranty timing-chain claim. It's not ULEZ-compliant (Euro 5), which rules it out for daily London driving. As the N47 ages, prices have softened — there's a real market for £3,000–£6,000 examples that look clean but carry hidden liability. This guide is built for that market.
| Full engine code | N47D20 |
|---|---|
| Configuration | I4 turbo diesel, common-rail |
| Production years | 2007-2014 |
| Applicable chassis | E81, E82, E87, E88, E90, E91, E92, E93, F20, F21, F30, F31, F32, F36, F10, F11, E84, F25, F26, F48 |
| Badge names | 116d, 118d, 120d, 318d, 320d, 325d, 420d, 520d, X1 18d, X1 20d, X3 20d, X4 20d |
| Real-world UK MPG | 42–52 mpg combined, 50–60 mpg motorway |
| Emissions / ULEZ | Euro 5, NOT ULEZ-compliant |
| Successor | B47 |
| Reliability score | 5 / 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 |
|---|---|---|---|---|
| Timing chain stretch / snap | Catastrophic | Very common | 60–120k mi | £1,500–£2,500 |
| EGR cooler failure / coolant leak | Serious | Common | 70–130k mi | £600–£1,100 |
| Swirl flap bolt shear | Catastrophic | Uncommon | 80–150k mi | £200–£400 |
| DPF (diesel particulate filter) regen failure | Moderate | Common | 40–100k mi | £400–£1,500 |
| Diesel injector failure | Moderate | Common | 80–150k mi | £350–£700 |
Timing chain stretch / snap
- Diesel-rattle on cold start that fades after 10-30 seconds
- Whirring or grinding noise from the rear of the engine (the chain is at the gearbox end)
- Engine warning light with cam/crank correlation fault codes (P0016, P0017)
What to do about it: Replace timing chain, guides and tensioner before 100,000 miles. Insist on receipts on any used purchase.
If ignored: Chain snaps → valves meet pistons → engine destruction. £4,000-£6,000 for a rebuilt or replacement engine.
UK repair exposure: £1,500–£2,500.
Recall / TSB: No formal recall in UK; subject of multiple class-action discussions. BMW UK have refused goodwill on most cases out of warranty.
Additional notes: Pre-2011 builds (typically pre-LCI E90/E91) have the chain at the rear of the engine — gearbox-out job, doubles labour cost. Post-2011 fronts are accessible but issue is not fully resolved until B47.
EGR cooler failure / coolant leak
- White smoke from exhaust when warm
- Coolant loss with no visible external leak
- Sweet smell from exhaust
- Low coolant warning
What to do about it: Inspect EGR cooler at every major service after 70k. Replace at first sign of internal leak.
If ignored: Coolant ingestion can hydrolock the engine. £4,000+ in worst case.
UK repair exposure: £600–£1,100.
Recall / TSB: BMW issued safety recall (NSC R/2018/151 in UK) for fire risk on N47/B47 EGR coolers — check VIN against DVSA recall database.
Swirl flap bolt shear
- Sudden loss of power
- Misfire / rough running
- Metallic debris on borescope inspection of intake
What to do about it: Many indies will remove and blank-plate the swirl flaps as a preventative — £200-400. Loses no measurable performance.
If ignored: If a flap or bolt enters the cylinder: bent valves, scored bores, full engine rebuild £4,000+.
UK repair exposure: £200–£400.
Recall / TSB: Inherited from M47 era — long-known issue, no manufacturer remedy.
DPF (diesel particulate filter) regen failure
- DPF warning light
- Reduced power / limp mode
- Strong smell during attempted regen
- Failed MOT on emissions
What to do about it: Drive at motorway speeds for 30+ minutes weekly. Avoid short city-only journeys. Use BMW LL-04 spec oil.
If ignored: Cracked DPF or full replacement: £1,500-£2,500.
UK repair exposure: £400–£1,500.
Additional notes: Most common on city-bound cars. A car that's done mostly motorway miles is much lower risk than one that did school runs.
Diesel injector failure
- Rough idle, particularly when cold
- Black smoke under load
- Knocking sound from one cylinder
- Increased fuel consumption
What to do about it: Use premium diesel (Shell V-Power, BP Ultimate) — anecdotal evidence it extends injector life. Replace the worst injector + recode at first sign.
If ignored: Damaged piston crown / cylinder bore. £3,000+ engine work.
UK repair exposure: £350–£700.
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, NOT BMW's 18,000-mile lifetime fill | Every 7,500 mi | £80–£130 | DIY |
| Fuel filter | Every 30,000 mi | £60–£110 | DIY |
| Air filter | Every 30,000 mi | £25–£50 | DIY |
| Coolant Every ~4 years, NOT lifetime | Every 60,000 mi | £120–£180 | Specialist |
| Brake fluid Every 2 years, NOT BMW's 4 years | Every 24,000 mi | £60–£100 | Specialist |
| Timing chain preventative replacement MOST IMPORTANT preventative on this engine. Skip at your peril. | At 80,000 mi | £1,500–£2,500 | Specialist |
| EGR cooler inspection Visual check during service; replace if seeping. Recall NSC R/2018/151 may apply. | Every 30,000 mi | £0–£50 | Specialist |
Long-term verdict
Capable of 250,000+ miles IF the timing chain is replaced preventatively. Pre-2011 builds are the highest risk — rear-mounted chain, expensive job, frequent failures. With chain done and a documented service history, the N47 is a robust diesel. Without proof of chain work past 80,000 miles, treat as a deferred maintenance liability worth £1,500-£2,500.
Buy, negotiate, or walk away
Buy
Post-2011 build (chain moved to the front of the engine), full BMW main dealer or known indie service history, documented chain replacement OR under 60k miles, EGR recall NSC R/2018/151 completed with paperwork, no smoke or rattle on a cold start.
Negotiate
Pre-2011 build with no chain history, 80k–120k miles, EGR recall outstanding but bookable. Use a £1,500–£2,500 chain bill as the negotiation floor — a clean post-2011 equivalent is worth more than the cheaper car plus repair.
Walk away
Audible rattle on a cold start that lasts longer than a couple of seconds. Evasive seller about service history. Swirl-flap debris found on a borescope. Pre-2011 chain, 120k+ miles, no history, no receipts — the maths almost never works.
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.
Check a specific N47 listing
Paste any BMW N47 listing, VIN, or registration — Bimmer.AI returns a N47-specific buyer report in 30 seconds.
Run a Bimmer.AI buyer report →Frequently asked questions
Is the BMW N47 engine reliable?
The N47 can be reliable when properly maintained, but its reputation is dominated by timing-chain risk. Pre-2011 builds have the chain at the rear of the engine, making replacement a £1,500–£2,500 specialist job. Look for strong service history, evidence of preventative chain work, and no cold-start rattle.
Which BMW models used the N47 engine?
The N47 appeared across many four-cylinder diesel BMWs: 1 Series (E81/E87/F20), 3 Series (E90/E91/E92/F30), 5 Series (F10/F11), X1 (E84/F48), and X3 (F25). Exact fitment depends on year, market, and trim — always verify chassis + engine, not just the 320d badge.
How much does N47 timing-chain replacement cost in the UK?
Expect £1,500–£2,500 at a BMW specialist including tensioner, guides, and related gaskets. Pre-2011 rear-chain cars sit at the top of that range (gearbox-out). Front-chain builds are cheaper to access. Get two quotes — prices vary significantly by region.
Is the N47 ULEZ-compliant?
No. The N47 is a Euro 5 diesel, so it's not exempt from London's ULEZ charge. The B47 that replaced it in 2014 is Euro 6 and ULEZ-compliant. If ULEZ compliance matters, the N47 is the wrong engine.
Should I buy an N47 BMW if the timing chain has not been replaced?
Only if the price reflects the risk AND the car has strong supporting evidence: no cold-start rattle, full service history, no fault codes, recent oil changes. If the seller is evasive, the car is priced as if it's clean, or you hear any rattle at all, treat it as a walk-away.
What else commonly fails on the N47?
Beyond the timing chain: EGR cooler internal leaks (subject to fire-risk recall NSC R/2018/151), swirl-flap bolt shear past 80k miles, DPF regeneration failure on city-only cars, and diesel injector wear past 100k miles. All of these are priced in on a realistic N47.