How to read your engine code in two minutes
The 17 characters of a VIN — and the four that decide which engine fits your car. A field guide for buyers and garages.
Buying a used or reconditioned engine without the right reference is expensive. The year and model name are not enough: two cars that look identical on the outside can carry different blocks, injectors, or exhaust layouts. The shortest path to certainty is the engine code — usually four characters stamped on the block or printed on the vehicle registration document — combined with the VIN, the 17-character chassis number that never lies about origin and equipment.
Where to find the engine code. On most European diesels and petrols, look for a flat machined pad on the block (often near the gearbox joint) with an alphanumeric code such as OM651, N47, EA888, or DW10. It may be oil-stained; a quick clean with brake cleaner and a phone photo is enough. If the stamp is unreadable, check the registration certificate (V5C in the UK, national certificate in France, Zulassungsbescheinigung in Germany): many states print an engine type field. Online VIN decoders can list the factory engine family, but treat them as hints only — we always cross-check against the physical code before quoting.
Reading the VIN. Positions 4–8 describe the model line and restraint type; position 9 is a check digit; the plant and serial are at the end. For compatibility, the most useful segment is often the model and restraint block together with the engine code from the car. The four characters of the engine code (for example CFF, N57, B47) matter more than model year alone because manufacturers mid-cycle swap hardware for emissions stages.
Common European codes in context. OM651 covers a wide swathe of Mercedes four-cylinder diesels; N47 and its successor B47 sit under many BMW four-cylinders; EA888 generation 2 and 3 differ in timing components; TDI PD and common-rail families are not interchangeable even when displacement matches; PSA HDi and DV6 lines need the exact suffix for turbo and EGR layout. Your garage already knows this in practice — our job is to match the donor engine to your VIN and code so the first start after fitting is uneventful.
If you cannot find the code. Send clear photos of the engine bay, the registration document, and any labels on the cam cover or timing belt area. We still prefer the stamped code, but we can narrow candidates from VIN plus photos. When in doubt we under-promise: we would rather decline a borderline match than ship a reference that costs you a week on the ramp.
When you are ready, use our quote form: enter the registration plate or full VIN, choose your delivery country, and we will confirm compatibility manually before sending a firm price and the four-test report for the allocated unit.