BMW B47 engine report, 120d F20 LCI
BMW B47 · 1 Series (F20)
2.0 LDieselInline-42015–2019
72/100
Checked by hand
[good]
Dependable, if the chain history checks out
Worth buying if the service history checks out.
ExcellentGoodSolidRiskyAvoid
- Known issues
- 8
- Critical
- 2
- Sources
- 70
Verdict
Owners mention two things far more than the rest: timing chain stretch with worn guides, and coking around the EGR valve and swirl flaps.
Both are common enough that a full service history is worth more here than a low odometer reading. DPF clogging and failed regenerations sit in the same bracket, usually on cars that never left town, so one with motorway miles behind it is the safer buy. Heavy oil consumption and ringland failure turn up very rarely.
Specs
- Displacement
- 2.0 L1,995 cc
- Layout
- Inline-4
- Fuel
- Diesel
- Compression
- 16.5:1
- Production
- 2014–present
- Chassis
- F20
- Generation
- LCI
- Fitted
- 2015–2019
Known issues
8 confirmed · sorted by severity
CriticalEGR cooler leak
The cooler for the recirculated exhaust gas develops an internal leak. Coolant disappears with no visible drip, and the exhaust may smell sweet or smoke white. Left alone, it contaminates the intake and can overheat the engine.
Symptoms
- Coolant Loss
- Burning Smell
- Smoke (White/Blue/Black)
- Warning Light
- Reduced Power Mode
How often
Common · Manufacturing defect. Can destroy the engine if ignored. Not safely drivable.
Evidence
3 owner reports back this, confidence 95/100.
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
Very rare · Design weakness. Does not normally destroy the engine. Not safely drivable.
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 · Age-related wear. Does not normally destroy the engine. Still drivable.
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.
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
Very rare · Age-related wear. Does not normally destroy the engine. Still drivable.
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
Very common · Expected maintenance. Can destroy the engine if ignored. Still drivable.
LowECU fault or wiring issue
ECU hardware fault or injector wiring loom degradation causing misfires or no-start conditions.
Symptoms
- Warning Light
- Misfire
How often
Occasional · Manufacturing defect. Does not normally destroy the engine. Still drivable.
LowEngine sensor failure
Crankshaft, camshaft, MAP, lambda/O2, or MAF sensor failure causing rough running, stalling, or incorrect fueling.
Symptoms
- Warning Light
- Rough Idle
- Misfire
How often
Occasional · Age-related wear. Does not normally destroy the engine. Still drivable.
Evidence
6 owner reports back this, confidence 40/100.
- Critical
- High
- Moderate
- Low
Timing chain stretch / guide wearfrom 149k km
DPF clogging / regeneration failurefrom 209k km
EGR valve / swirl flap cloggingfrom 100k km
Check the car you're looking at
Set the mileage of the car you're looking at. Problems owners say start before it are the ones to ask the seller about; the next ones are what to budget for.
km
1 already past · 0 coming up
Already past: ask for proof
Owners say these start before this mileage. Nothing tells us whether this car had them fixed, so ask, and ask for the invoice.
The next 30k km
Nothing owners report starts in this stretch.
Further on Timing chain stretch / guide wear, DPF clogging / regeneration failure
No reliable mileage EGR cooler leak, Piston ringland failure, ECU fault or wiring issue, Engine sensor failure, Excessive oil consumption
Too few owners said at what mileage these start, so they are not placed above.
Buying checklist
BMW B47 (120d F20 LCI) · Buying checklist
Sources
Updated 15 Sept 2026 · scoring v2.7
Behind this report sit 70 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.