BMW N47 engine report
BMW N47 · 120d (F20/F21)
2.0 LDieselInline-42011–2014
40/100
[risky]
Quick and frugal, as long as the chain is quiet
Worth buying, but only on the right car. Chain work on record or a clean cold-start check, normal DPF differential pressure readings, and oil changes kept under 15,000 km.
ExcellentGoodSolidRiskyAvoid
- Known issues
- 15
- Critical
- 3
- Sources
- 95
Verdict
Listen to a cold start before anything else, because chain stretch and guide wear are very common on this engine.
Ask whether the chain has ever been replaced. The high-pressure fuel pump and DPF clogging are common too, and a pump failure rarely stops at the pump. Injectors, the water pump, EGR clogging and oil leaks show up as well, mostly as rare faults. This isn't an engine to pay strong money for.
Specs
- Displacement
- 2.0 L
- Layout
- Inline-4
- Fuel
- Diesel
- Compression
- 16.1:1-16.5:1
- Production
- March 2007 - September 2015
- Chassis
- F20/F21
- Generation
- F20
- Fitted
- 2011–2014
Known issues
15 confirmed · sorted by severity
CriticalPiston ringland failure
Piston ringland cracking under high cylinder pressure/heat, common on tuned forced-induction engines.
Symptoms
- Power Loss
- Smoke (White/Blue/Black)
- Misfire
How often
Rare · Design weakness. Can destroy the engine if ignored. Not safely drivable.
Evidence
8 owner reports back this, confidence 50/100.
CriticalOil pump wear / sludge buildup
Oil pump wear or sludge accumulation (often from extended oil-change intervals) reducing oil pressure and lubrication.
Symptoms
- Warning Light
- Knocking Noise
How often
Rare · Design weakness. Can destroy the engine if ignored. Not safely drivable.
Evidence
9 owner reports back this, confidence 45/100.
CriticalHead gasket failure
Head gasket failure, often preceded by overheating; can lead to a warped head or cracked block if not addressed.
Symptoms
- Coolant Loss
- Smoke (White/Blue/Black)
- Warning Light
How often
Very rare · Age-related wear. Does not normally destroy the engine. Not safely drivable.
Evidence
5 owner reports back this, confidence 50/100.
HighHigh-pressure fuel pump failure
HPFP wear or failure, sometimes shedding metal debris into the fuel system.
Symptoms
- Misfire
- Warning Light
- Hesitation
How often
Common · Design weakness. Can destroy the engine if ignored. Not safely drivable.
Evidence
34 owner reports back this, confidence 55/100.
ModerateTiming chain stretch / guide wear
Timing chain elongates or plastic guides wear prematurely, causing rattle, incorrect valve timing, or in severe cases chain failure.
Symptoms
- Knocking Noise
- Cold Start Rattle
- Warning Light
How often
Very common · Design weakness. Does not normally destroy the engine. Still drivable.
Evidence
107 owner reports back this, confidence 55/100.
ModerateDPF clogging / regeneration failure
Diesel particulate filter clogs, especially with short/urban trips that prevent regeneration, triggering warning lights or limp mode.
Symptoms
- Warning Light
- Reduced Power Mode
How often
Common · Environmental. Does not normally destroy the engine. Still drivable.
Evidence
42 owner reports back this, confidence 55/100.
ModerateExcessive oil consumption
Worn valve stem seals, piston rings, or a clogged PCV/oil separator system causing oil consumption above manufacturer spec.
Symptoms
- Oil Consumption
- Smoke (White/Blue/Black)
How often
Rare · Design weakness. Does not normally destroy the engine. Still drivable.
Evidence
14 owner reports back this, confidence 50/100.
ModerateWater pump failure
Water pump seal or bearing failure (mechanical or electric pump), causing coolant loss.
Symptoms
- Coolant Loss
- Warning Light
How often
Rare · Design weakness. Does not normally destroy the engine. Still drivable.
Evidence
7 owner reports back this, confidence 45/100.
ModerateDual-mass flywheel / clutch wear
Dual-mass flywheel wear causing rattle/vibration, often coinciding with clutch replacement interval.
Symptoms
- Excessive Vibration
- Knocking Noise
How often
Very rare · Expected maintenance. Does not normally destroy the engine. Still drivable.
Evidence
4 owner reports back this, confidence 50/100.
LowIntercooler failure or leak
Intercooler core cracking or pipe seal failure, causing boost loss.
Symptoms
- Power Loss
How often
Rare · Age-related wear. Does not normally destroy the engine. Still drivable.
Evidence
8 owner reports back this, confidence 50/100.
LowEGR valve / swirl flap clogging
EGR valve, EGR cooler, or intake swirl flaps clog with carbon/soot, causing rough running or limp mode.
Symptoms
- Rough Idle
- Reduced Power Mode
- Warning Light
How often
Rare · Expected maintenance. Does not normally destroy the engine. Still drivable.
Evidence
9 owner reports back this, confidence 45/100.
LowFuel injector failure
Injector wear, sticking, or seal failure causing misfires, rough running, or fuel leaks.
Symptoms
- Misfire
- Rough Idle
- Fuel Smell
How often
Rare · Design weakness. Does not normally destroy the engine. Still drivable.
Evidence
12 owner reports back this, confidence 40/100.
LowGlow plug failure
Glow plug wear or failure causing hard cold starts on diesel engines.
Symptoms
- Warning Light
How often
Rare · Design weakness. Can destroy the engine if ignored. Still drivable.
Evidence
9 owner reports back this, confidence 40/100.
LowOil leak from seals or gaskets
Valve cover gasket, rear main seal, or front main seal degradation causing external oil leaks.
Symptoms
- Oil Consumption
How often
Very rare · Design weakness. Does not normally destroy the engine. Still drivable.
Evidence
4 owner reports back this, confidence 45/100.
LowThermostat / temperature sensor failure
Thermostat sticking open or closed, or temperature sensor drift, causing incorrect operating temperature.
Symptoms
- Warning Light
How often
Very rare · Age-related wear. Does not normally destroy the engine. Still drivable.
Evidence
2 owner reports back this, confidence 40/100.
- Critical
- High
- Moderate
- Low
High-pressure fuel pump failurefrom 115k km
Timing chain stretch / guide wearfrom 129k km
DPF clogging / regeneration failurefrom 161k km
Piston ringland failurefrom 186k km
Oil pump wear / sludge buildupfrom 220k km
Head gasket failurefrom 257k km
Excessive oil consumptionfrom 155k km
Water pump failurefrom 129k km
Showing the 8 highest-impact of 15 dated issues. The rest are in the list above.
Buying checklist
0 of 14 checked
Sources
Updated 15 Sept 2026 · scoring v2.7
Behind this report sit 95 owner posts, forum threads and official records. Nothing gets on the list on one person's word. It takes a recall, or owners on separate platforms describing the same fault. The score then sets how often a problem turns up against the damage it does.