BMW B47 diesel engine explained: reliability and common issues
The BMW B47 is the 2.0-litre four-cylinder diesel in many BMWs. How it improved on the N47, the models and outputs, common issues such as EGR and DPF, and maintenance tips for long life.
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The BMW B47 is the 2.0-litre four-cylinder diesel engine used in many of BMW's most popular models, including the 118d, 320d, 520d, X1 and X3. Introduced in 2014, it replaced the N47 and became one of BMW's most widely used engines.
It combines strong torque, low fuel consumption and improved reliability compared with its predecessor. In this article we explain how the BMW B47 is built, how it differs from the N47, the models and outputs, common issues and maintenance tips.
From N47 to B47
The N47, used from 2007, was efficient and powerful, but some early versions became known for timing chain problems. Our article on BMW timing chain problems explains those issues.
The B47 was developed as part of BMW's modular engine family, alongside the petrol B38, B48 and B58 and the diesel B37 and B57. It brought many improvements in durability, refinement and emissions. The timing chain remained at the rear of the engine, but it was redesigned and is generally considered much more durable.
The B47 also introduced better noise insulation and smoother running, which made BMW's diesel models feel more refined. Many drivers say that, from inside the car, a modern B47 sounds much less like a diesel than older engines.
How the BMW B47 is built
Key features of the BMW B47 include:
- A 2.0-litre four-cylinder diesel with an aluminium crankcase.
- Common-rail direct injection with high injection pressure.
- Turbocharging, with single or two-stage turbo systems depending on the power level.
- Exhaust gas recirculation (EGR) to reduce nitrogen oxides.
- A diesel particulate filter (DPF) and, in many later versions, SCR with AdBlue.
Our articles on the BMW DPF and BMW AdBlue explain these emissions systems.
Models and power outputs
The B47 has been used in many models with outputs typically from around 116 hp to more than 230 hp in two-stage turbo versions. Examples include:
- 1 and 2 Series: 116d, 118d, 120d, 218d, 220d.
- 3 and 4 Series: 318d, 320d, 420d.
- 5 Series: 518d and 520d.
- X1, X2, X3, X4 in several versions.
- MINI models with diesel engines.
Exact outputs depend on the model, year and market. Our F30 320d and F10 520d buying guides explain two of the most popular cars with diesel engines.
Common issues
The B47 is generally reliable, but these points deserve attention:
- EGR system: the EGR valve and cooler can clog with soot. BMW carried out a recall on EGR coolers of some diesel engines to address a safety risk. Check whether recall work has been done on the car you own or plan to buy.
- DPF clogging: frequent short trips prevent regeneration. Our article on the BMW DPF explains the symptoms.
- AdBlue system faults on later cars, such as sensor or heater problems.
- Injectors on very high-mileage engines.
- Turbocharger wear if oil maintenance is poor.
Most of these issues are linked to driving pattern and maintenance.
The early N47 timing chain issue is not considered a common problem on the B47, but listening to the engine on a cold start remains a sensible check on any used diesel BMW.
Maintenance that matters
To keep a BMW B47 healthy:
- Change the oil regularly with the correct diesel-approved oil. Low-ash oils protect the DPF.
- Drive longer distances regularly so the DPF can regenerate.
- Use quality fuel.
- Replace fuel and air filters on time.
- Have recalls and software updates done.
Our article on BMW Condition Based Service explains how BMW plans maintenance.
Who should choose a B47 diesel?
A B47 diesel suits drivers who:
- Cover high mileages, especially on motorways.
- Want low fuel consumption and strong torque for overtaking and towing.
- Do longer trips regularly, which keeps the DPF healthy.
For mostly short trips in town, a petrol engine is often the better choice. Our article on BMW diesel or petrol explains how to decide.
Buying a car with a B47
When buying a used BMW with a B47:
- Check the service history and oil change intervals.
- Ask about EGR recall work.
- Look for DPF and AdBlue warning messages.
- Listen to a cold start for unusual noises from the rear of the engine.
- Read the fault memory.
Our complete checklist for buying a used BMW covers other checks.
Why the B47 matters
The B47 made BMW's popular diesel models more reliable and efficient. For many drivers, a B47-powered 320d or 520d offers an excellent combination of performance, comfort and fuel economy, especially on long motorway journeys.
With regular maintenance and the right driving pattern, a B47 can cover very high mileages.
BMW B47 diesel engine at a glance
| Item | Details |
|---|---|
| Introduced | 2014 |
| Layout | 2.0-litre four-cylinder diesel |
| Predecessor | N47 |
| Turbo | Single or two-stage depending on output |
| Emissions | EGR, DPF, SCR with AdBlue in many versions |
| Power range | Around 116 hp to over 230 hp |
| Key checks | EGR recall, DPF, AdBlue, service history |
Frequently asked questions
Is the BMW B47 reliable?
Generally yes. It is considered much more reliable than early N47 engines, especially when serviced correctly.
Does the B47 have timing chain problems?
The B47 uses a redesigned chain at the rear of the engine and is generally considered much more durable than early N47 engines.
Which BMWs have the B47 engine?
Many models, including the 118d, 320d, 420d, 520d, X1 and X3.
Is a B47 diesel good for short trips?
Not ideal. Frequent short trips can clog the DPF. Diesels suit longer journeys.
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