National 2377 Engine Crankshaft Seal - Rear

National 2377 Engine Crankshaft Seal Overview

The National 2377 engine crankshaft seal is designed to provide reliable sealing performance for various Ford and Mercury vehicles. Engineered with durable fluoro-elastomer material, this oil seal helps maintain engine integrity by preventing oil leaks around the crankshaft.

• Inside diameter: 3.750 inches (95.250 mm)
• Outside diameter: 4.506 inches (114.450 mm)
• Thickness/width: 0.362 inches (9.190 mm)
• Material: Fluoro-elastomer for enhanced chemical and heat resistance
• Redicoat surface treatment for improved sealing and durability
• Compatible with Ford and Mercury models including Bronco, Econoline series, Mustang, and more
• Part number: 2377

Detailed Product Description

The National 2377 crankshaft seal is part of the 2000 series and features a 35-type design optimized for sealing the crankshaft in engines. Its fluoro-elastomer construction offers resistance to heat, oil, and other automotive fluids, ensuring long-lasting performance under demanding conditions. The seal’s precise dimensions—3.750 inch inside diameter and 4.506 inch outside diameter—make it suitable for a range of Ford and Mercury vehicles, including the Bronco, F-150, Mustang, and various Econoline models. The Redicoat treatment enhances the seal’s surface, reducing wear and improving sealing reliability over time.

Applications and Common Issues Addressed

• Prevents oil leaks around the engine crankshaft
• Reduces contamination of engine components by sealing out dirt and debris
• Helps maintain proper engine oil pressure
• Addresses wear and tear from heat and friction in older or high-mileage vehicles
• Replaces worn or damaged crankshaft seals in Ford Bronco, Mustang, Econoline vans, and Mercury models

Installation Notes and Tips

Ensure the crankshaft and housing bore are clean and free of debris before installation. Verify the housing bore diameter of approximately 4.501 inches (114.330 mm) matches the seal’s outside diameter for proper fit. Use appropriate tools to press the seal evenly into place without damaging the fluoro-elastomer material. Avoid over-tightening or misalignment to prevent premature seal failure.

Quality Assurance and Warranty

National engine crankshaft seals are manufactured to meet industry standards for durability and performance. The 2377 part number is backed by National’s quality control processes to ensure consistent fit and function. Warranty details should be confirmed with the original equipment manufacturer or distributor.