BMW E90 E91 E92 335d M57N2 Crankcase Breather Vent Valve Oil Separator 7809512

BMW E90 E91 E92 335d M57N2 Crankcase Breather Vent Valve Oil Separator is a precision component of the crankcase ventilation system, specifically designed for the M57N2 engine in 3 Series models. It is responsible for effectively separating oil mist from gases before they return to the intake, which promotes stable diesel engine operation and reduces contamination of the intake system. Thanks to a design consistent with BMW factory solutions, this component helps maintain the proper operating parameters of the power unit.

Specifications and technical data

• SKU: 7809512-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7809512
• Substitutable numbers: 11127809512, 7809512, 11127803790, 7803790, F01C470034
• Category: Oil Pumps & Parts

Function and role in the lubrication system

The breather with an oil separator in the M57N2 engine is responsible for the controlled discharge of gases from the crankcase and their reintroduction into the intake system. The integrated vent valve stabilizes pressure, which helps reduce blow-by, excessive smoke, and carbon deposit buildup in the manifold. A properly functioning separator reduces the amount of oil entering the intake, which promotes smooth operation of the turbocharging and injection systems.

Compatibility and fitment for BMW 335d M57N2

The presented element has been developed with the specifics of the M57N2 engine in mind, as installed in the BMW 3 Series E90, E91, and E92 generations in the 335d version. This ensures a proper fit to factory mounting points and compatibility with the original breather hose geometry. As a result, installation is straightforward, without the need for modifications or non-factory workarounds.

The product belongs to the Oil pumps and parts group, which highlights its close connection to the lubrication system and oil circulation in the power unit. Using a component with parameters consistent with BMW solutions helps maintain predictable engine operating conditions, especially under the demanding operating conditions typical of powerful diesel engines.

Characteristics of the used component

The offered vent valve with oil separator is a genuine BMW part in used condition, which means it retains the factory design and materials while offering an attractive price-to-functionality ratio. A used component of this type is often chosen as a reasonable alternative to new parts, especially during comprehensive service work on older 3 Series vehicles.

In the case of ventilation system components, it is important to maintain compliance with the vehicle manufacturer's solutions – this helps avoid problems with leaks, incorrect vacuum, or uncontrolled oil ingress into the intake. Choosing a genuine, used breather with an oil separator limits the risks typical of random aftermarket replacements with uncertain specifications.

Importance of regular breather inspection in the M57N2 engine

In powerful diesel engines, such as the 335d, an efficient crankcase ventilation system has a direct impact on the durability of engine accessories. A worn or faulty oil separator can accelerate the contamination of the intake manifold, valves, and turbocharging components. Replacing the breather with a functional unit helps limit these phenomena and maintain stable engine operating parameters in the long term.

Before the winter season, when the engine operates more frequently at lower temperatures and under higher loads, it is worth including a ventilation system check in your service plan. Practical tips on preparing your car for low temperatures and lists of components worth verifying can be found in the article Winter essentials: which used car parts are worth checking and replacing before the frost?.

Expanding BMW lubrication system service

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other elements from the same group, such as oil lines, housings, or pressure control elements, check out the available parts in the BMW Oil pumps and parts category.

This approach allows you to organize key elements related to oil circulation and ventilation in a single service stage, which reduces the risk of future service downtime and makes it easier to maintain a consistent vehicle repair history.