National 3051N Engine Crankshaft Seal - Front or Upper

Engine Crankshaft Seal for Subaru and More

National 3051N is a metric engine crankshaft oil seal built with silicone sealing material and a clockwise-spiral lip design for controlled sealing performance. It is sized for a 42.000 mm shaft and 55.120 mm housing bore, making it a direct-fit option for a range of Subaru, Mercury, Mazda, Saab, and Volkswagen applications.

Key Features

• Part number: 3051N
• Engine crankshaft seal / oil seal for sealing system service
• Silicone sealing material for consistent contact at the shaft
• Clockwise-spiral lip design
• Metric dimensions: 42.000 mm shaft, 55.120 mm outside diameter, 8.000 mm width
• Series 3000, Type 33
• Compatible with Subaru WRX STI, Impreza, Forester, Legacy, Outback, Baja, and Saab 9-2X applications listed below

Product Details

National has supplied sealing solutions for more than 75 years, and the 3051N reflects that focus on dimensional accuracy and modern sealing design. This crankshaft seal uses silicone sealing material and a spiral lip profile to maintain contact at the shaft while matching the specified housing bore and metric dimensions. It is a practical replacement for vehicles such as the Subaru WRX STI, Subaru Impreza, Subaru Forester, Subaru Legacy, Subaru Outback, Subaru Baja, Saab 9-2X, Mercury Mountaineer, Mazda B4000, and Volkswagen Vanagon with VW 090 transmission applications. This part cross-references MAHLE 67808 and Bosch 16507 for the same application.

What This Part Helps Address

• Engine oil seepage at the crankshaft seal area
• Oil residue around the front or upper engine sealing surface
• Loss of sealing integrity from age, heat, or wear
• Service replacement for a damaged or hardened crankshaft seal
• Leak-related contamination near the timing or transmission interface

Installation Notes and Tips

Verify shaft diameter, housing bore, and seal orientation before installation. The clockwise-spiral lip design should be installed in the correct direction for the application, and the sealing surface should be clean and free of scoring. Confirm vehicle-specific fitment by year, make, model, and position before assembly. Fits 2015-2019 Subaru WRX STI, Upper; 2004-2014 Subaru Impreza, Upper and N/A; 2004-2013 Subaru Forester, Upper; 2005-2012 Subaru Legacy, Upper; 2005-2010 Mercury Mountaineer, Front; 2005-2009 Subaru Outback, Upper; 2006 Saab 9-2X, Upper; 2004-2006 Subaru Baja, Upper; 2005 Mazda B4000, Front; 2004 Mercury Mountaineer, Front; 1980-1991 Volkswagen Vanagon, N/A.

Quality Assurance

National is a long-established sealing brand known for engineering replacement oil seals for current and legacy vehicles. The 3051N is built to the listed metric dimensions and sealing specifications for dependable service in the applications shown.