Dongfeng LoongGine Engine parts Valve stem oil seal assembly 10BF11-07036

Engineered to prevent excessive consumption (oil burning) while maintaining proper valve lubrication, this oil seal assembly features a dual-lip design with a primary sealing lip and a secondary dust lip. The primary lip—made of high-performance fluoroelastomer (FKM) or nitrile rubber (NBR, for standard-temperature engines)—creates a tight seal against the valve stem, controlling the amount of oil that enters the valve guide (allowing only a thin, lubricating film: ≤0.5 mg per valve cycle). The secondary dust lip blocks carbon deposits, metal particles, and other contaminants from entering the valve guide, preventing abrasion of the valve stem and seal. Rigorous testing shows the assembly reduces oil consumption by 30-40% compared to single-lip seals, minimizing exhaust smoke (caused by oil burning) and extending the service life of the catalytic converter (if equipped) and oxygen sensors

The 10BF11-07036 valve stem oil seal assembly is built to withstand the extreme thermal and mechanical stress of engine valve systems. For high-temperature exhaust valves, the primary sealing lip uses FKM rubber, which maintains elasticity and sealing performance at temperatures up to 250°C (intermittent up to 300°C)—resisting hardening, cracking, or degradation from prolonged exposure to exhaust heat. For intake valves (lower temperature environments: up to 150°C), NBR rubber is used for its excellent oil resistance and cost-effectiveness. Both rubber materials are reinforced with a metal spring (typically stainless steel 304) embedded in the primary lip, ensuring constant contact pressure against the valve stem even as the rubber ages. The metal sleeve (if present) is made of galvanized steel, providing structural support and corrosion resistance against oil and coolant residues

To ensure consistent performance and easy installation, each oil seal in the assembly undergoes precision machining to meet tight dimensional tolerances. The inner diameter of the seal has a tolerance of ±0.02 mm, ensuring a snug fit on the valve stem without causing excessive friction (which would accelerate valve stem wear). The outer diameter is machined to match the valve guide bore with a tolerance of ±0.03 mm, preventing the seal from slipping or rotating during engine operation. The seal’s height is controlled to ±0.1 mm, ensuring proper alignment with the valve spring retainer and avoiding interference with other valve train components. Additionally, the sealing lips are polished to a surface roughness of Ra ≤0.2 μm, reducing friction between the lip and valve stem—extending both the seal’s service life (typically 80,000-100,000 kilometers) and the valve stem’s wear resistance

By effectively controlling oil flow and blocking contaminants, the 10BF11-07036 valve stem oil seal assembly plays a critical role in protecting Dongfeng LoongGine engines. Preventing excessive oil from entering the combustion chamber reduces carbon buildup on valves, piston tops, and spark plugs (or fuel injectors), which can cause misfires, reduced compression, and decreased engine power. Blocking contaminants from the valve guide prevents abrasive wear of the valve stem and guide, maintaining proper valve clearance and reducing the risk of valve sticking (a common cause of engine overheating or damage). The assembly requires no periodic maintenance once installed—its durable materials and robust design ensure long-term reliability. Each seal is packaged individually (or in sets matching the engine’s valve count) with clear part number labeling, simplifying inventory management for fleet workshops and ensuring the correct seal is used for intake or exhaust valves