The N47 is the four-cylinder diesel in a huge number of 1 Series, 3 Series, X1 and X3 cars from the late 2000s and early 2010s. People search for a used one because the car is otherwise sound and a replacement engine is cheaper than another car. The part that decides whether that engine is worth buying is the timing chain.
Why the chain matters
On the N47 the chain sits at the gearbox end of the engine. A worn guide or a stretched chain does not show up as a simple top-end rattle you can ignore. If the chain jumps, the valves and pistons meet. Changing the chain means the engine has to come out, so the cost of a neglected chain is close to the cost of another engine.
Later N47D20C and N47D20D units had revised guides. That does not make every late engine perfect, and it does not make every early engine scrap. It means you ask about the exact code and about any chain work, instead of buying from the badge on the boot.
What to listen for
If the engine is still in a car, the useful test is a cold start after it has sat overnight. A brief tick that disappears in a second can be injectors. A rattle from the back of the engine that lasts several seconds, or that returns at idle, needs a proper look before you pay.
A chain that has already been replaced is not a bad sign. Ask who did it, and whether the guides, tensioner and crank bolt were part of the job. An engine sold with no history is judged on the stamp, the sump and the photos, not on a promise.
What we look at on the block
We read the code cast and stamped on the block and match it to the listing. On an N47 that code is the difference between an early chain engine and a later one, and between a 116d, a 320d and a 25d tune. The oil pan also matters: an xDrive car uses a different pan and pickup from a rear-wheel-drive car.
Oil that smells of diesel, a mayonnaise film under the cap, or metal in the drained oil is a reason to walk away. A used engine can have normal staining. It should not have fresh metal paste in the filter housing.
Fitment
An N47 from a manual 320d will not drop into an automatic xDrive X3 just because both say 2.0 diesel. The sump, the flywheel or flexplate, the turbo and the engine wiring have to match the car the engine is going into. Send the VIN before you pay. The check is free.
Full N47 guide · N47D20C for a 120d
After it is fitted
A replacement N47 still needs a new oil filter, the correct oil and a cooling system that holds pressure. The chain you were worried about is inside this engine. Do not reuse the old oil, and do not ignore a rattle on the first cold start after fitting. That start is the moment to stop and look, not the moment to road-test it for an hour.
The glow plugs, the fuel filter and the engine mounts are cheap beside another chain job. Fit them while the engine is out if the old ones are tired. Code the injectors if your workshop replaced them. Then send the car for a proper bleed and a check for air in the fuel, which feels like a bad engine and is often just a loose line.
The yard is at Andreas Meyer Straße 38, 22113 Hamburg. Call or WhatsApp +49 15510 030835, or email autowerkeengines@gmail.com, Monday to Friday, 9:00 to 16:00 CET. Shipping is 249 € per order. We are an independent seller, not BMW AG.