Engine Rear Crankshaft Main Oil Seal Double Lip Auto Seal Parts

1. Product Overview

2. Core Functions

• Oil Sealing: Effectively seals engine crankcase lubricating oil to prevent oil leakage from the rear end of the crankshaft, avoiding engine oil loss and pollution.
• Dust & Water Proof: Blocks external dust, sediment and muddy water from entering the engine interior to protect internal precision parts.
• Accessory Protection: Prevents engine oil from contaminating the clutch plate, effectively avoiding clutch slippage, jitter and failure caused by oil leakage.

3. Product Structure Types

• One-piece Design (Mainstream): Integrated annular skeleton oil seal with metal shell, rubber lip and stainless steel garter spring. Some models are equipped with an aluminum retainer for easy and accurate installation, widely used in modern passenger cars and new diesel engines.
• Two-piece Design (Traditional): Split upper and lower structure, mainly applicable to old-style large-displacement gasoline engines. Gradually replaced by integrated seals due to high installation difficulty.
• PTFE Lip High-performance Type: Adopts PTFE composite lip, featuring low friction, high temperature resistance and wear resistance, suitable for high-power and high-load engines.

4. Material Options & Features

• NBR (Nitrile): Temperature range: -30℃ ~ +120℃. Cost-effective, excellent compatibility with conventional engine oil, ideal for ordinary gasoline engines.
• ACM (Polyacrylate): Temperature range: -20℃ ~ +150℃. Good heat and oil resistance, cost-effective for medium-load engines.
• FKM (Viton): Temperature range: -20℃ ~ +200℃. Superior high temperature resistance, aging resistance and oil corrosion resistance, the preferred material for commercial vehicles and engineering machinery engines.
• PTFE: Temperature range: -40℃ ~ +260℃. Ultra-low friction coefficient, anti-wear and high pressure resistance, suitable for high-performance and extreme working condition engines.

5. Product Specifications

• Size Standard: ID (Inner Diameter) × OD (Outer Diameter) × Width (mm)
• Lip Type: Single lip (conventional sealing) / Double lip (enhanced dustproof & sealing)
• Structure: Metal steel shell + stainless steel tension spring + rubber/PTFE sealing lip
• Quality Standard: 100% OEM replacement quality, strict factory inspection

6. Common Failure Causes

• Seal lip aging, hardening and cracking caused by long-term high temperature and oil erosion
• Lip wear and spring fatigue relaxation leading to slow oil seepage
• Damage and flange of sealing lip caused by incorrect installation
• Excessive crankshaft runout and abnormal crankcase pressure accelerating seal wear
• Scratches and rust on the crankshaft surface affecting sealing performance

7. Professional Installation Tips

• Rubber lip seals: Apply a thin layer of clean engine oil for lubrication before installation
• PTFE lip seals: Dry installation only, do not lubricate
• Install vertically with special tools to avoid tilt and lip scratch
• Ensure the sealing lip faces the engine oil side and the spring is firmly installed without falling off
• Check and repair crankshaft surface scratches before installation

8. Application Scope

9. Product Advantages

• Precision manufacturing, perfect fit with original equipment
• Excellent sealing performance, no oil leakage, long service life
• High temperature and aging resistance, adaptable to harsh working conditions
• Complete specifications, support OEM customization and bulk wholesale