BMW F20 118d (N47 / B47 Engines)—Overview
At a Glance
The BMW 1 Series in F20 form (five-door, 2011–2019) and F21 (three-door, 2012–2019) came with a wide engine lineup: N13, N20, N47, N55, B37, B38, B47, B48, B58. The 118d holds a special place in that lineup—it’s the best-selling diesel version of the 1 Series and the sensible choice for everyday duty.
The main dividing line is the model year. Pre-facelift (pre-LCI) cars carry the N47 diesel with its timing chain at the flywheel end. From the spring 2015 LCI, it was replaced by the modular B47D20—with a reworked timing chain relocated to the front.
Engines
| Version | Engine | Design Feature |
|---|---|---|
| Pre-LCI | N47D20 | Timing chain at the flywheel end |
| From LCI (spring 2015) | B47D20 | Modular diesel, timing chain reworked and moved to the front |
Both configurations are 2.0-liter four-cylinder diesels. The difference in timing drive layout determines both the difference in typical faults and the difference in buying advice.
Service Intervals
| Service | Interval |
|---|---|
| Engine oil change | every 12,500 miles or 1 year |
| Fuel filter replacement | every 37,000 miles |
| ZF 8HP automatic transmission fluid (ATF) change | every 50,000–62,000 miles |
| EGR cooler check (B47 recall) | one time only |
The EGR cooler check sits in the service plan as a one-time operation, tied to the recall campaign covering early B47 engines.
Common Problems
N47 Timing Chain (Pre-LCI)—Code 2A82
The most common and most expensive problem on the pre-facelift F20 118d. Early F20s with the N47 show the same picture as the E90 320d: the timing chain sits at the flywheel end, which makes access difficult and labor more expensive than on engines with the timing drive up front. Chain wear shows up as synchronization faults, above all 2A82.
B47 EGR Cooler—Recall Campaign
Early B47 engines came with EGR coolers with inadequate sealing. The problem grew widespread enough to trigger an official recall campaign. The first thing an F20 118d owner with a B47 should do is check whether the campaign has been carried out on the specific VIN.
The typical diagnostic codes for this component are 490B (EGR cooler) and 4908 (EGR cooler changeover).
Water Pump and Thermostat—Code P0128
Failure is possible at relatively low mileage, and it can send the engine into limp mode. The cooling system signal is P0128.
The thermostat is a topic of its own. Some engines use a map-controlled thermostat, others a conventional wax type. The difference affects replacement cost: the map-controlled unit costs more, the wax type less.
CP4 High-Pressure Fuel Pump (HPFP) on the N47 / N57
The CP4 high-pressure fuel pump (HPFP) appears on the N47 and N57. Typical symptoms: hard starting (long crank) and fuel rail pressure faults. The matching code is 480A (DDE rail pressure).
The EGR System Overall
Seized EGR valves and destroyed EGR coolers are a characteristic problem on diesels and gasoline engines alike. A contaminated valve can be cleaned; a destroyed cooler needs replacement.
Diagnostic Codes
| Code | What It Means |
|---|---|
| 2A82 | N47 timing chain |
| P0128 | Cooling system (water pump / thermostat) |
| 490B | EGR cooler |
| 4908 | EGR cooler changeover |
| 480A | DDE rail pressure (HPFP) |
Source Data Discrepancies
The 118d material contains two internal contradictions worth keeping in mind when you evaluate a specific car.
EGR cooler recall. The main text ties the recall campaign to the B47, while the related article on EGR cooler replacement cost cites recall 0061230400 for the N47. That means the recall topic touches both engines in different formulations, and the campaign status needs to be confirmed by VIN rather than taken from a single source.
Water pump on the 118d. The main text describes the pump as electric; the related article assigns the diesel pump to the mechanical type. The only reliable conclusion comes from the actual equipment fitted to the specific car.
Buying Advice
Pre-LCI (N47). Buy only with the timing chain already replaced. Without documented proof of the chain job, the chain is a hidden risk that can end in an engine rebuild of comparable cost.
LCI (B47). Check the EGR recall status first. With the campaign performed, the car turns into a very economical compact diesel—the EGR cooler is replaced free of charge under an active recall.
The overall logic. On the N47, the timing chain is the factor that decides the deal; on the B47, it’s the recall status. Everything else—the water pump, thermostat, and fuel injection hardware—is secondary and gets covered by a standard inspection.
What Shops See Most
The most common pre-facelift 118d complaint is timing chain noise and synchronization faults on the N47. Post-LCI cars typically come in for EGR cooler leaks and faults handled under the recall campaign. Water pumps and thermostats are replaced less often, usually at the point where limp mode and P0128 have already arrived.
FAQ
Timing chain or timing belt on the 118d?
Chain. On the N47 it sits at the flywheel end, and it’s the main maintenance topic.
When did the B47 arrive in the F20 118d?
With the spring 2015 LCI, when the B47D20 replaced the N47D20.
Is the F20 118d worth buying?
An LCI (B47) car with the EGR recall completed is a very economical everyday car. Pre-LCI—only with the timing chain already replaced.
Bottom Line
The F20 118d is a rational compact diesel, but the split by model year is sharp. On pre-LCI cars, the deciding question is the N47’s flywheel-side timing chain and its replacement. On LCI cars, it’s the status of the EGR cooler recall on the B47. Check those two items before the deal, and nothing else under the hood will come as a surprise.