Audi A6 C8 Window Guide Seal Gasket Moulding Rear Left N/S 4K9839431B

Audi A6 C8 Window Guide Seal Gasket Moulding Rear Left N/S is a precision body component responsible for stable window guidance and reducing noise and vibrations while driving. The original design, dedicated to the rear left side of the body, ensures a proper fit to the door frame and maintains the factory operating parameters of the window mechanism. As a result, acoustic comfort and the sealing of the door area remain at a level consistent with the manufacturer's specifications.

Specifications and technical data

• SKU: 4K9839431B
• Mark: Audi
• Condition: Used
• OEM Part Number: 4K9839431B
• Substitutable numbers: 4K9839431B, 4K9 839 431 B
• Location on the vehicle: Rear, Left
• Category: Door Seals

Purpose and function in the Audi A6 C8 body

The presented window guide seal has been designed specifically for the rear left part of the Audi A6 C8 generation body. The component operates in the door frame area, guiding the window along the correct trajectory and acting as a barrier to prevent water, dust, and wind noise from entering the cabin. Dedicated vehicle placement minimizes the risk of improper installation and eliminates issues with window geometry.

Construction and performance properties

The Audi A6 C8 Window Guide Seal Gasket Moulding Rear Left N/S belongs to a group of wear-and-tear components that may degrade over time due to the operation of the window lifting mechanism and exposure to atmospheric factors. Using the original design allows for maintaining:

• stable window guidance throughout its entire range of motion,
• reduction of lateral play and unwanted vibrations,
• proper cooperation with the window regulator mechanism and the door frame,
• visual consistency with other door trim elements.

Thanks to this, the window opening and closing mechanism operates smoothly, and the risk of jamming or uneven closing is reduced.

Benefits of using the original window guide seal

Choosing the original Audi A6 C8 Window Guide Seal Gasket Moulding Rear Left N/S is particularly important in premium class vehicles, where both comfort and precision of workmanship matter. Using a component from the Door Seals group with factory geometry allows for:

• maintaining proper pressure of the window against the door frame,
• reducing wind noise at higher speeds,
• limiting moisture ingress into the door structure,
• preserving the aesthetics and consistency of the side body line.

This solution is highly recommended when replacing a worn or damaged guide, especially when symptoms such as increased noise, difficulty in closing the window, or leaks in the rear left window area appear.

Component condition and service application

The offered window guide seal is an aftermarket component, which allows for economical repair while maintaining the original design. This type of component is suitable for both standard replacement of a worn seal and post-accident repairs when it is necessary to restore the proper operation of the window in the rear left door. Selecting parts compatible with the Audi design facilitates service work and reduces installation time.

Expanding the scope of service work

If you are planning a comprehensive repair or upgrade of the door area in your Audi and need other elements from the same group, such as additional perimeter seals, window trim strips, or door frame seals, check the available parts in the Audi Door Seals category.

To better plan service work on the body and systems interacting with the body, it is also worth checking out practical guide materials – you will find helpful information in the article Summer heat vs. cooling system: used radiators and fans as a guarantee of savings, which shows how to consciously choose used components in various vehicle systems.