Mercedes X166 Window Quarter Rubber Rear Left N/S A1666808900

Mercedes X166 Window Quarter Rubber Rear Left N/S is an original body component designed for installation in the rear left section of the vehicle. Thanks to its precise fit for the specific body generation, it ensures a stable window seating, reduces noise penetration, and supports the proper operation of the water drainage system. It is a practical solution for users who want to restore the factory sealing parameters and comfort in their Mercedes.

Specifications and technical data

• SKU: A1666808900
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1666808900
• Substitutable numbers: A1666808900, A 166 680 89 00
• Location on the vehicle: Rear, Left
• Category: Window Seals, Gaskets & Trims

Purpose and function of the component

The presented Mercedes X166 Window Quarter Rubber Rear Left N/S has been designed specifically for the X166 body type. Its task is to maintain a proper seal between the window and the bodywork, which limits the ingress of water, dust, and air gusts into the passenger cabin. A correctly selected seal also contributes to the reduction of aerodynamic noise, which translates into higher acoustic comfort while driving.

Its placement in the rear zone, on the left side of the vehicle, makes this component significant both for protecting the interior and for stable window guidance in the frame. Proper fitting of the seal also helps to reduce unwanted window vibrations and minimizes the risk of excessive wear.

Construction and fit for the Mercedes X166 body

The seal belongs to the group of body components referred to as Window seals and trims, which means it has been developed to work with the factory window frame construction. The seal profile is adapted to the geometry of the rear quarter window in the Mercedes X166, ensuring that the installation proceeds in a predictable manner, without the need for bodywork modifications.

The original origin from the Mercedes brand ensures dimensional compatibility with factory mounting points as well as appropriate material stiffness and flexibility. This is particularly important for components operating in variable temperature conditions, exposed to UV radiation, moisture, and window movement in the guide channel.

Condition, service application, and benefits of installation

The item is offered in a used condition, which allows for an economical replacement of the seal while maintaining the manufacturer's original specifications. For many Mercedes X166 users, this is a reasonable service solution when the existing seal shows signs of wear, such as leaks, window fogging, or increased cabin noise.

Replacing the rear left quarter window seal is particularly recommended in situations where:

• water leaks appear in the rear part of the cabin,
• an increase in noise is noticeable at higher speeds,
• the seal edges are perished, cracked, or deformed,
• the window operates with noticeable play in the frame.

Selecting an original seal from the same model group allows for restoring proper window guidance and limiting the risk of further damage to adjacent components, such as finishing trims or side upholstery.

Integration with other body components and area of application

The rear left quarter window seal works with the glass, the door or body frame, and adjacent finishing trims. A correctly installed component creates a cohesive sealing system in the rear part of the vehicle, which is important both for passenger comfort and for protection against corrosion around the body edges.

Due to its location in the rear zone of the vehicle, the seal is exposed to road debris, rainwater, and temperature changes. Proper selection and installation of this component is an important step in maintaining stable operating conditions, especially in cars used all year round.

Modernization expansion – other seals and trims for Mercedes

If you are planning a comprehensive repair or modernization of the window area in your Mercedes and need other elements from the same group, such as additional side window seals, finishing trims, or window frame seals, check the available parts in the Mercedes Window seals and trims category.

More about the use of used parts in Mercedes vehicles

If you are considering a broader renovation of your car and want to better understand how to consciously choose used body and equipment components for models such as Mercedes, it is worth reading the practical tips on vehicle modernization from the 1998–2012 period in the article The second life of a youngtimer – how used car parts rejuvenate cars from the 1998–2012 model years.