BMW 3 Series E90 E91 LCI N57 Diesel Sealing Cap Oil Filler Hose Neck 7804048

BMW E90 E91 LCI N57 Diesel Oil Filler Cap is an original lubrication system component designed for N57 diesel engines in facelifted BMW 3 Series models. This practical cap ensures a tight seal for the engine oil filler opening, reducing the risk of leaks and contamination. Thanks to its genuine BMW origin, it maintains the correct geometry and fit for the valve cover in Diesel engines.

Specifications and technical data

• SKU: 7804048
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7804048
• Substitutable numbers: 11127804048, 7804048
• Fuel type: Diesel
• Category: Other Engine Parts

Purpose and Function of the Oil Filler Cap

The oil filler cap in the N57 engine is responsible for maintaining the seal of the lubrication system in the upper part of the power unit. A correctly selected component:

• prevents the escape of oil vapors and mist,
• protects the engine interior from dust and moisture during operation,
• stabilizes operating conditions around the valve cover,
• facilitates safe topping up of service oil.

For modern BMW N57 Diesel engines, the correct cap is crucial for maintaining proper operating parameters and engine bay cleanliness.

Compatibility with N57 Diesel Units

The presented cap has been designed for use in N57 diesel engines installed in facelifted (LCI) BMW E90 and E91 series. This ensures the correct thread profile, diameter, and seal, which translates to:

• secure seating in the oil filler port,
• no need for valve cover modifications,
• consistency with the original design of the power unit.

As a result, the cap can be used as a replacement part during standard maintenance or for repairs related to the lubrication system.

Product Characteristics and Condition

The offered BMW oil filler cap comes from the manufacturer's original parts line, which helps maintain factory quality standards. The item is classified as used, meaning it has been previously operated but can still perform its function after installation in another vehicle. This type of part is particularly attractive in situations where:

• the original cap has suffered mechanical damage (cracking, wear),
• the part was lost or misplaced during service,
• a quick and economical replacement is needed without compromising on an OEM component.

Choosing an original cap from the aftermarket allows for consistency with other lubrication system components while reducing repair costs.

Why Use an Original BMW Cap in a Diesel Engine

In diesel engines like the N57, the oil filler cap operates at elevated temperatures and in contact with oil vapors. Using a component from the BMW range promotes:

• maintaining proper sealing under varying operating temperatures,
• preserving the material's appropriate resistance to engine oil,
• reducing the risk of improper fit, which is common with imprecisely dimensioned aftermarket alternatives.

For users who prioritize proper service maintenance and want to maintain a design consistent with the manufacturer's project, choosing such a cap is a technically sound solution.

Service Expansion and Related Items

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other parts from the same group, such as additional service caps, covers, or small mounting elements, check the available parts in the Other BMW category.

When working on diesel units, it is also worth expanding your knowledge on the design differences between sports and standard versions of engines and chassis – an article describing the comparison of technical solutions in the RS range might be helpful, available here: Audi RS vs. Other Models – What Lies Under the Hood and Chassis?.