2780100431 BEMWQ Crankcase Ventilation Oil Separator for Mercedes Benz C218 M157

The BEMWQ Crankcase Ventilation Oil Separator (Part No.: 2780100431) is a critical emission and engine protection component designed for Mercedes-Benz vehicles equipped with the M157 V8 Biturbo engine, specifically compatible with the C218 (CLS 63 AMG) chassis. Positioned within the cylinder head or valve cover area, this unit acts as a vital part of the Positive Crankcase Ventilation (PCV) system. Its primary function is to separate oil mist and liquid droplets from the crankcase blow-by gases before these gases are recirculated into the intake manifold for combustion, ensuring that only clean air returns to the engine .

• Precision OEM Specification:​ Manufactured to match the original equipment standard 2780100431, ensuring exact housing dimensions, internal baffle geometry, port alignment, and mounting points for a seamless fit on the M157 engine without modification .

• Efficient Oil Separation Design:​ Engineered with internal impingement baffles or cyclone separation structures that effectively strip heavy oil droplets from the air-oil vapor stream, allowing separated oil to drain back to the sump while clean vapor continues to the intake .

• Durable Material Construction:​ Built using high-grade, heat-resistant polymer or composite materials designed to withstand long-term exposure to hot engine oil vapors, fuel vapors, and constant thermal cycling without cracking or warping .

• Integrated Ventilation Function:​ Designed to work in conjunction with the engine’s crankcase pressure control, often incorporating or connecting directly to the PCV valve mechanism to ensure proper crankcase pressure regulation across all RPM ranges .

• Prevents Oil Consumption & Intake Contamination:​ Eliminates excessive oil entry into the intake system, which prevents "burning oil" (blue smoke), reduces abnormal oil consumption, and minimizes oily carbon deposits on intake manifolds, throttle bodies, and intake valves .

• Stops Oil Leaks from Pressure Buildup:​ Resolves crankcase pressure issues caused by a clogged or failed separator; by keeping the ventilation path clear, it prevents excessive internal pressure that can otherwise force oil past valve cover gaskets, rear main seals, and other engine seals .

• Restores Engine Performance & Emissions:​ Ensures the MAF sensor and air-fuel mixture are not contaminated by oil mist, helping to eliminate rough idle, hesitation, and lean/rich fuel trim codes (e.g., P0171, P0174), while also supporting cleaner exhaust emissions .

• Cost-Effective PCV System Repair:​ Provides a dependable and economical alternative to OEM parts for replacing a common failure point on higher-mileage M157 engines (often prone to internal sludge blockage or plastic housing cracks), restoring the integrity of the crankcase ventilation system .