BMW M47 Engine Reliability Guide
The BMW M47 is the 2.0-litre four-cylinder turbo diesel of 1998 to 2007: E46 318d and 320d, E39 520d, E87 118d and 120d, E90 318d and 320d, E60 520d and E83 X3 2.0d. Tough, simple and thrifty, with a front-mounted timing chain that rarely troubles anyone, unlike the N47 that replaced it.
Quick verdict
Do the swirl flap removal on any 2001 to 2007 car, watch the turbo and the crank pulley rubber, and an M47 will do 250,000 miles. Not ULEZ-compliant, and the youngest examples are approaching twenty years old, so the buying decision is as much about rust, cooling and electrics as the engine. The E46 320d and E87 120d built BMW's UK diesel following on this engine.
What is the BMW M47?
M47 cars are the cheapest BMW diesels in the country: E46 320d at £1,000 to £3,500, E87 118d and 120d at £1,500 to £4,000, early E90 320d at £2,000 to £4,500, all with 130,000 to 250,000 miles. The M47TU2 (2004 onwards, 163 bhp in the 320d and 120d) is the sweet spot. The one preventative is swirl flaps; the one expensive failure is the turbo.
| Full engine code | M47TUD20 |
|---|---|
| Configuration | I4 turbo diesel, common-rail, variable-geometry turbo, front-mounted timing chain |
| Production years | 1998-2007 |
| Applicable chassis | E46, E39, E60, E61, E83, E87, E90, E91 |
| Badge names | 118d, 120d, 318d, 320d, 520d, X3 2.0d |
| Real-world UK MPG | 40 to 50 mpg combined, 48 to 56 mpg motorway |
| Emissions / ULEZ | Euro 4, NOT ULEZ-compliant |
| Successor | N47 |
| Reliability score | 7 / 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 |
|---|---|---|---|---|
| Inlet manifold swirl flap failure (M47TU and TU2, 2001 to 2007) | Catastrophic | Common | 80 to 160k mi | £150 to £300 |
| Turbocharger failure | Serious | Common | 100 to 170k mi | £800 to £1,500 |
| Diesel injector wear | Moderate | Common | 100 to 170k mi | £250 to £450 |
| EGR valve and inlet manifold clogging | Moderate | Very common | 80 to 150k mi | £200 to £450 |
| Crankshaft vibration damper and pulley delamination | Serious | Common | 100 to 170k mi | £250 to £400 |
| Glow plugs and control module | Mild | Common | 80 to 150k mi | £120 to £350 |
| Fuel rail pressure regulator and MAP or MAF sensor faults | Mild | Common | 80 to 150k mi | £100 to £250 |
Inlet manifold swirl flap failure (M47TU and TU2, 2001 to 2007)
- Usually none until failure
- Sudden misfire and loss of power
- Metal debris in the inlet
What to do about it: Remove the flaps and fit blanking plates, £150 to £300.
If ignored: Flap enters the cylinder: bent valves and piston damage, £3,000 to £5,000.
UK repair exposure: £150 to £300.
Recall / TSB: No recall.
Additional notes: The original 1998 to 2001 M47D20 (136 PS, E46 320d and E39 520d) has no swirl flaps and is not affected.
Turbocharger failure
- Blue or black smoke
- Whistle rising with revs
- Loss of boost and limp mode
- Oil in the intercooler pipework
What to do about it: Regular oil changes; check the vane actuator moves freely.
If ignored: Debris ingested or engine runaway.
UK repair exposure: £800 to £1,500.
Diesel injector wear
- Rough idle and chuffing
- Hard warm starting
- Black smoke
What to do about it: Leak-off test, then replace and code the worst injector.
If ignored: Piston damage.
UK repair exposure: £250 to £450.
EGR valve and inlet manifold clogging
- Sluggish response
- Smoke
- EGR fault codes
What to do about it: Clean the inlet when doing the swirl flap job.
If ignored: Restricted inlet and more soot.
UK repair exposure: £200 to £450.
Crankshaft vibration damper and pulley delamination
- Cracked rubber on the crank pulley
- Wobble and belt squeal
- Vibration at idle
What to do about it: Inspect past 100,000 miles; replace preventatively.
If ignored: Pulley separates and throws the belt.
UK repair exposure: £250 to £400.
Glow plugs and control module
- Hard cold starts
- White smoke on start-up
What to do about it: Replace as a set.
If ignored: Cold-start problems and emissions failure.
UK repair exposure: £120 to £350.
Fuel rail pressure regulator and MAP or MAF sensor faults
- Intermittent limp mode
- Hesitation
- Engine warning light that clears and returns
What to do about it: Diagnose with live data before replacing parts.
If ignored: Drivability only.
UK repair exposure: £100 to £250.
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) | Every 7,500 mi | £70 to £120 | DIY |
| Fuel filter | Every 30,000 mi | £50 to £100 | DIY |
| Air filter | Every 30,000 mi | £20 to £45 | DIY |
| Coolant | Every 60,000 mi | £100 to £160 | Specialist |
| Brake fluid | Every 24,000 mi | £60 to £100 | Specialist |
| Swirl flap removal and inlet clean (2001 to 2007 cars) Do it now if there is no receipt | At 100,000 mi | £150 to £300 | Specialist |
| Crank damper inspection or replacement | At 100,000 mi | £250 to £400 | Specialist |
Long-term verdict
Tough, simple and thrifty; the E46 320d and E87 120d built BMW's UK diesel following on this engine. Front-mounted chain that rarely troubles anyone, unlike the N47 that replaced it. Do the swirl flap removal on any 2001 to 2007 car, keep an eye on turbo health and crank pulley rubber, and it will do 250,000 miles. Not ULEZ-compliant, and the youngest examples are approaching twenty years old, so condition beats mileage.
Buy, negotiate, or walk away
Buy
Swirl flaps removed and blanked with an invoice, turbo pulling cleanly, crank pulley damper replaced, EGR and manifold cleaned, no rust in the sills or rear arches, cooling system healthy.
Negotiate
Original swirl flaps (£150 to £300 to remove), turbo whistle, pulley rubber cracking, glow plug module fault, injector leak-off past 150,000 miles.
Walk away
Smoke plus turbo noise with no turbo history, a swirl flap already gone, structural rust, or a car whose age-related bills exceed its value.
Check a specific M47 listing
Paste any BMW M47 listing, VIN, or registration. Bimmer.AI returns a M47-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 M47 engine reliable?
Very. It is a simple, iron-block diesel with a front-mounted chain that almost never fails. The known items are swirl flaps on 2001 to 2007 manifolds (remove them, £150 to £300), turbocharger wear past 100,000 miles (£800 to £1,500), injector leak-off, EGR clogging, crank pulley delamination and glow plugs. Bimmer.AI scores it 7 out of 10.
Does the M47 have the N47 timing chain problem?
No. The M47's chain is at the front of the engine, is conventionally sized and rarely gives trouble even past 200,000 miles. The rear-mounted chain that stretches and costs £1,500 to £2,500 to replace belongs to the N47 that replaced the M47 in 2007. If you want a cheap BMW diesel without the chain conversation, the M47 is the answer.
Which BMWs have the M47?
E46 318d and 320d (1998 to 2005), E39 520d (2000 to 2003), E87 118d and 120d (2004 to 2007), E90 / E91 318d and 320d (2005 to 2007), E60 / E61 520d (2005 to 2007) and E83 X3 2.0d (2004 to 2007). Also Rover 75 and MG ZT CDT, which used a BMW-supplied M47 derivative.
Is the M47 ULEZ-compliant?
No. All M47 cars are Euro 3 or Euro 4 diesels, below the Euro 6 standard the ULEZ requires. Outside London's zone and other clean-air zones it does not matter.