BMW N47 diesel explained: the four-cylinder with the timing chain at the back

The BMW N47 is a 2.0-litre four-cylinder diesel engine that BMW used from 2007 to around 2015. It powered hugely popular models such as the 320d, 520d and 120d, combining strong torque with low fuel consumption.

The BMW N47 is also known for one unusual design choice: its timing chain sits at the back of the engine. In this guide we explain the versions, the cars, the timing chain issue and how to keep the engine healthy.

What the BMW N47 is

The N47 replaced the older M47 diesel in 2007. It has an aluminium block, four valves per cylinder, common-rail direct injection and a turbocharger. Many versions also have a diesel particulate filter and, later, other emission systems.

It was a modern and efficient engine for its time. In a car such as the E90 320d it offered strong pulling power from low revs and very good fuel economy on long journeys.

Its successor, the B47, arrived from 2014. Our article on the BMW B47 diesel explains the newer engine and what BMW changed.

N47 versions and power

The N47 was sold in many outputs, depending on the model and the year:

• Around 116 to 143 PS: models badged 116d, 118d and 318d.
• Around 163 to 184 PS: the most common versions, badged 120d, 320d, 520d and xDrive20d.
• Around 204 PS: a twin-turbo version, used for example in the 123d.

Torque is high for a four-cylinder, often between 300 and 400 Nm, depending on the version. Exact figures differ between models, years and markets.

The N47 also appeared in some MINI diesel models, so parts and specialist knowledge are widely available.

Which BMWs use the N47

The N47 was used in a long list of models from around 2007 to 2015:

• E81, E82, E87 and E88 1 Series and the early F20 1 Series.
• E90, E91, E92 and E93 3 Series and the early F30 and F31 3 Series.
• F10 and F11 5 Series with the 518d, 520d and 525d of some years.
• X1 E84 and X3 E83 and F25 with the xDrive18d and xDrive20d.

If you are not sure which engine your car has, our article on BMW engine codes explains how to find it.

Why the BMW N47 timing chain is famous

On the N47, the timing chain sits at the back of the engine, on the gearbox side. BMW chose this layout to save space and improve crash safety, but it makes timing chain work much more difficult.

On many earlier engines, especially from around 2007 to 2011, the chain or its guides could wear too quickly. The typical warning sign is a rattling or whining noise from the back of the engine, often most noticeable at idle or when the engine is warm.

If the problem is ignored, the chain can break, which usually causes serious engine damage. Because the chain is at the back, the engine normally has to be removed to replace it, so the repair is expensive.

BMW revised the parts during production. When buying, ask whether the timing chain has been replaced and ask for the invoice. Our article on BMW timing chain problems explains the symptoms in more detail.

Other common N47 problems

Besides the timing chain, owners report some typical diesel issues:

• Swirl flaps and intake carbon: our article on BMW swirl flaps explains the risk.
• EGR valve and cooler: soot build-up can cause poor running. See our article on BMW EGR valve problems.
• Diesel particulate filter: short trips can block it. Our article on the BMW DPF explains regeneration.
• Turbocharger and boost hoses: worn turbos or split hoses reduce power.
• Injectors: a worn injector can cause rough running or smoke.

None of these is unusual for a modern diesel, but they should be considered when buying a high-mileage car.

How to keep a BMW N47 healthy

Good maintenance is the best way to protect an N47:

• Change the oil more often than the long official interval, using a BMW-approved low-ash oil. Clean oil helps the timing chain and the turbo.
• Listen for timing chain noise and act early if you hear a rattle from the back of the engine.
• Drive longer distances regularly so the DPF can regenerate.
• Keep records of all work, especially the timing chain.

An N47 with an updated timing chain and a good service history can be a reliable and very economical engine. Our article on buying a high mileage BMW explains what else to check.

BMW N47 at a glance

Item	Details
Engine type	2.0-litre turbocharged four-cylinder diesel
Production	2007 to around 2015
Power	Around 116 to 204 PS
Torque	Around 260 to 400 Nm, depending on the version
Timing chain	At the back of the engine (gearbox side)
Known issue	Timing chain and guide wear on many earlier engines
Main cars	1 Series, 3 Series, 5 Series, X1, X3
Successor	B47

Frequently asked questions

What is the main problem with the BMW N47?

The best-known issue is timing chain and guide wear on many earlier engines. A rattle from the back of the engine is the typical warning sign.

Why is the N47 timing chain so expensive to replace?

Because the chain sits at the back of the engine, on the gearbox side. In most cases the engine has to be removed to replace it.

Which BMWs have the N47 engine?

Many 1 Series, 3 Series and 5 Series diesels from around 2007 to 2015, plus the X1 and X3 with the 18d and 20d engines.

How do I know if the timing chain was replaced?

Ask for the invoice in the service history. A specialist can also listen to the engine and check for typical chain noise.

What replaced the BMW N47?

The B47, a newer 2.0-litre four-cylinder diesel introduced from 2014.

Sources

• BMW Group – engine technology information
• BMW owner's manuals – E90 and F10 diesel models
• Workshop experience with BMW four-cylinder diesel engines