641250 - Continental Motors OEM Nose Seal Assembly

641250 – Continental Motors OEM Nose Seal Assembly

Available now on the Airparts.aero Marketplace.

Overview

The Continental 641250 is a genuine OEM crankshaft nose seal assembly, a critical component designed to prevent engine oil leakage from where the propeller shaft exits the front of the crankcase. This seal assembly is engineered by Continental Motors to provide a reliable, long-lasting barrier against oil loss while withstanding the constant rotation of the crankshaft and the high-temperature environment at the front of the engine. Comprised of a unique, two-piece split design, the 641250 allows for replacement of the seal without the monumental task of splitting the engine case, making it a key component for both engine overhaul and field maintenance.

Key Features

• Effective Sealing Design: Utilizes a two-piece (split) seal and slinger ring combination. This design works hydrodynamically, using a channel and a slinger to direct oil away from the crankcase parting surface, preventing leaks and keeping the engine and propeller clean.
• OEM Quality Materials: Manufactured from proprietary materials selected by Continental for their optimal balance of flexibility, durability, and resistance to degradation from hot engine oil and atmospheric conditions.
• Field-Replaceable: The split-seal design is a hallmark of Continental engine serviceability, allowing an A&P mechanic to replace a leaking seal in the field without removing the engine from the airframe or performing a complete teardown.
• Precision Fit: As a genuine Continental OEM part, it is manufactured to the exact dimensional tolerances required for a perfect fit around the crankshaft and within the crankcase groove, ensuring reliable sealing performance.
• Genuine OEM Part: Ensures you are using a component that meets the stringent quality and material requirements of the original engine type certificate, guaranteeing airworthiness and proper function.

Technical Specifications

• Part Number: 641250
• Component Type: Crankshaft Nose (Propeller Shaft) Seal Assembly
• Design: Two-Piece Split Seal with Slinger Ring
• Material: Proprietary Oil-Resistant Compound
• Mating Component: Crankshaft Oil Slinger P/N 641249 (often replaced concurrently)
• Applicable Service Document: Continental Service Bulletin M84-15 R1 provides detailed installation instructions.
• Certification: FAA Production Approval

Engine Compatibility

The Continental 641250 nose seal assembly is specified for use on a wide variety of Continental's most popular large-bore, direct-drive engines. It is imperative to consult the specific engine's Illustrated Parts Catalog (IPC) to verify the correct part number for your application.

• Compatible Engine Series:
  • O-470, IO-470, TSIO-470
  • IO-520, TSIO-520
  • GTSIO-520
  • IO-550, TSIO-550

Applications

The 641250 seal assembly has a singular but vital application:

• Crankshaft Oil Sealing: Prevents engine oil from leaking out of the front of the crankcase, keeping the propeller, cowling, and windscreen free from oil spray.
• Engine Overhaul & Repair: A mandatory replacement item during any engine overhaul and the primary component used to address a leaking front crankshaft seal in the field.

Why Choose 641250?

An oil-streaked cowling or propeller is more than a cosmetic issue—it’s a sign of a failing seal that can lead to significant oil loss over time. Choosing a genuine Continental 641250 OEM seal is the only way to ensure a durable, long-lasting repair that meets the engine manufacturer's specifications. The material and design have been tested and proven over millions of flight hours. For a component this critical to clean and reliable engine operation, there is no substitute for the quality and peace of mind that comes with using a genuine Continental part.

Order Your 641250 Nose Seal Assembly Now

Eliminate oil leaks and keep your aircraft clean with a genuine Continental 641250 crankshaft nose seal. Visit Airparts.aero to order this essential OEM part today.

The Continental 641250 nose seal assembly is an engineered solution to the dynamic challenge of sealing a rotating shaft. The system functions by using the associated oil slinger (P/N 641249) to hydrodynamically "throw" oil into a collection channel, which is then scavenged. The two-piece 641250 seal itself acts as the final barrier. The success of its installation is highly dependent on proper technique, as outlined in Continental Service Bulletin M84-15. This procedure involves meticulously cleaning the case groove, using a non-hardening sealant like Permatex Form-A-Gasket No. 2, and carefully placing the split line of the seal at the top of the crankcase to prevent gravity-induced leaks. Adhering to this procedure with a new OEM 641250 seal is fundamental to achieving a dry, leak-free engine front.

Note: Installation of this component must be performed by a certified A&P mechanic in strict accordance with the current, applicable Continental Motors Overhaul and Maintenance Manuals, as well as Service Bulletin M84-15 or its latest revision. Improper installation will result in continued or worsening oil leaks.