How Do I Know if I Have an N51 or N52 BMW 6-Cylinder Engine?
The late model non-M, non-turbocharged, BMW 6-cylinder engines used in the US market BMW 1, 3, 5, x and Z models from the late 2000s through mid 2000-teens, were produced in two variants for US distribution, known as the N51 and N52. The N52 is the standard Low (or UL – Ultra Low) Emissions Vehicle (LEV or ULEV) version and the N51 is the Super Ultra Low Emissions Vehicle (SULEV) version intended for states that employ the most stringent vehicle emissions standards. In the US, the N51 was installed in various 128i, 128ic, 328i, 328xi and 328ic models.
States that received vehicles with the N51 engine include; Arizona, California, Connecticut, District of Columbia, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington. Don’t be surprised to find N52 models registered in these states … or …. N51 models in the other states.
Why should you know whether your BMW has an N51 or an N52 engine? When ordering engine, emissions, fuel system and some other parts, you will need to clarify if you have the N51 or the N52. Failure to do so may very well result in the wrong parts being ordered.
So, how do you know which engine you have?
1) You can share the VIN with the BAVauto advisors, who can then use the VIN to verify the engine in your BMW.
2) Under the engine hood, the emissions control information sticker will note if the vehicle is a LEV or ULEV (N52) or SULEV (N51). The sticker is often on the underside of the hood itself.