National 3698 Engine Crankshaft Seal - Rear

Overview of National 3698 Engine Crankshaft Seal

The National 3698 engine crankshaft seal is designed for reliable sealing performance in various GM and Dodge vehicles. Engineered with a fluoro-elastomer material and a counter-clockwise spiral lip design, this oil seal helps maintain engine integrity by preventing oil leaks around the crankshaft.

• Inside diameter: 2.988 inches (75.9 mm)
• Outside diameter: 3.748 inches (95.2 mm)
• Thickness/width: 0.374 inches (9.5 mm)
• Material: Durable fluoro-elastomer for heat and chemical resistance
• Helix type: Counter-clockwise spiral lip design for effective sealing
• Housing bore compatibility: 3.740 inches (95 mm)
• Part number: 3698, Series 3000 oil seal

Technical Details and Specifications

This National 3698 crankshaft seal is part of the Series 3000 line, known for its engineered sealing solutions in automotive engines. The fluoro-elastomer construction offers enhanced resistance to high temperatures and automotive fluids, making it suitable for demanding engine environments. The counter-clockwise spiral lip design improves sealing efficiency by directing oil back into the engine, reducing leakage and contamination risks. With precise dimensions including a 2.988-inch shaft diameter and a 3.748-inch outside diameter, this seal fits housing bores measuring approximately 3.740 inches, ensuring a secure and accurate fit.

Compatible Vehicles and Applications

This engine crankshaft seal is compatible with a range of vehicles from Buick, Chevrolet, Dodge, GMC, Jeep, Oldsmobile, and Pontiac. It fits models such as the Chevrolet Camaro, S10, and Lumina; Jeep Cherokee, Wrangler, and TJ; Dodge Dakota and Comanche; Buick Century and Skylark; Pontiac Firebird and Sunbird; and several others including the Acadian, Astro, Calais, Celebrity, Cutlass series, Fiero, Grand Am, Monza, Omega, Phoenix, S10 Blazer, S15, S15 Jimmy, Safari, Scrambler, Starfire, T1000, Wagoneer, and CJ5/CJ7.

Common Issues Addressed by National 3698 Crankshaft Seal

• Prevents oil leaks around the crankshaft area
• Reduces engine contamination from external debris
• Maintains proper oil pressure and lubrication
• Protects engine components from premature wear
• Helps avoid costly engine repairs due to seal failure

Installation Notes and Tips

Ensure the crankshaft and housing bore are clean and free of debris before installation. Verify the seal orientation matches the counter-clockwise spiral lip design for optimal sealing. Use appropriate tools to press the seal evenly into the housing bore without damaging the lip or seal body. Avoid excessive force or misalignment during installation to maintain seal integrity and performance.

Quality Assurance and Warranty

National’s 3698 crankshaft seal is manufactured to meet industry standards for durability and performance. The fluoro-elastomer material and precision engineering provide reliable sealing under typical engine operating conditions. While specific warranty details may vary, National products generally come with a limited warranty against manufacturing defects, ensuring confidence in product quality.