National 710785 Engine Crankshaft Seal - Front

Overview of National 710785 Engine Crankshaft Seal

The National 710785 engine crankshaft seal is designed for precise fitment and reliable sealing in various BMW models. Engineered with fluoro-elastomer material and a clockwise-spiral lip design, this oil seal ensures effective protection against oil leaks and contaminants.

• Inside diameter: 2.559 inches (65.000 mm)
• Outside diameter: 3.118 inches (79.200 mm)
• Thickness/width: 0.787 inches (20.000 mm)
• Helix type: Clockwise-spiral lip design for enhanced sealing
• Material: Durable fluoro-elastomer for high resistance to heat and chemicals
• Housing bore compatibility: 3.110 inches (79.000 mm)
• Part number: 710785, Series 710700

Detailed Product Description

This National 710785 crankshaft seal is specifically engineered to maintain engine integrity by preventing oil leakage around the crankshaft. The fluoro-elastomer construction offers excellent resistance to high temperatures, oils, and automotive fluids, making it suitable for demanding engine environments. The clockwise-spiral lip design improves sealing efficiency by directing contaminants away from the shaft, reducing wear and extending service life. With precise dimensions including a 2.559-inch inside diameter and a 3.118-inch outside diameter, this seal fits securely within the housing bore of 3.110 inches, ensuring a tight and reliable fit.

Compatible BMW Models

This crankshaft seal is compatible with a wide range of BMW vehicles, including but not limited to the 1 Series M, 128i, 135i, 135is, 3 Series models such as 323i, 325i, 328i, 330i, 335i, and their xDrive variants, as well as 4 Series models like 435i and Gran Coupe versions. It also fits 5 Series models including 525i, 528i, 530i, 535i, and their xDrive and GT variants, 6 Series models such as 640i and Gran Coupe, 7 Series including 740i and 740Li, ActiveHybrid 3, 5, and 7, M2, M3, M4, M235i, X Series (X1, X3, X4, X5, X6), and Z4. This extensive fitment ensures compatibility with many BMW engines requiring this specific seal size and design.

Common Applications and Issues Addressed

• Prevents oil leaks around the crankshaft area
• Protects engine components from dirt and contaminants
• Reduces risk of engine damage due to oil loss
• Maintains proper engine oil pressure and lubrication
• Helps avoid costly repairs related to seal failure

Installation Notes and Tips

When installing the National 710785 crankshaft seal, ensure the sealing surface and shaft are clean and free of debris. Use appropriate tools to press the seal evenly into the housing bore without damaging the lip or seal body. Verify the seal orientation matches the clockwise-spiral lip design for optimal performance. Lubricate the seal lip lightly with engine oil before installation to reduce initial wear. Follow manufacturer torque specifications for any related components during reassembly.

Quality Assurance and Warranty

National engine seals are manufactured to meet OEM specifications, ensuring reliable performance and durability. The fluoro-elastomer material provides resistance to heat, oil, and chemicals commonly found in automotive engines. This product is part of the National 710700 series, known for consistent quality and fitment accuracy. Warranty coverage details should be confirmed with the original equipment manufacturer or distributor.