Mercedes W166 Window Glass Rear Right O/S Quarter Side Black AS3 A1666702812

Visual condition of the part

The product shows signs of use visible in the photos.

Mercedes W166 Window Glass Rear Right O/S Quarter Side Black AS3 is an original body component from the Car windows group, designed for installation in the rear section of the vehicle. The product ensures proper lateral body rigidity, correct interior illumination, and a consistent, factory-original look of the vehicle's side profile.

Specifications and technical data

• SKU: A1666702812
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1666702812
• Substitutable numbers: A1666702812, A 166 670 28 12
• Location on the vehicle: Rear, Right
• Color: Black
• Category: Car Glass

Purpose and function of the quarter glass

The rear quarter glass in the Mercedes W166 model is responsible for illuminating the passenger compartment, stabilizing the side of the body, and maintaining the original glazing geometry. Thanks to its precise profile and fitment to the body lines, the installation process is predictable, and once installed, the component creates a seamless surface with the other windows.

A properly selected quarter glass contributes to:

• maintaining the factory lateral structural rigidity,
• reducing noise and vibrations transmitted to the interior,
• proper adhesion of seals and trim moldings.

Color and visual fitment

The element is finished in a black color variant, which allows for an aesthetic integration with factory moldings, frames, and seals used in the Mercedes W166. The dark edge of the glass makes it easier to mask the mounting adhesive and ensures a uniform, clean appearance of the side body section.

Such a finish helps maintain the vehicle's stylistic consistency, especially in configurations with tinted windows or optical packages, where the continuity of the glazing line is important.

Vehicle placement and installation aspects

The glass is designed for installation in the rear part of the body on the right side, in the quarter panel area. Precise fitment to the specific body model reduces the risk of leaks and facilitates proper seating in the frame.

During installation, it is worth paying attention to:

• thorough cleaning of the contact surface,
• using an appropriate bonding system recommended for automotive body glass,
• checking for even pressure around the entire perimeter of the glass.

Characteristics of the used product

As an aftermarket element, the quarter glass retains its original geometry and body fitment parameters, which is crucial for post-accident repairs or replacing damaged glazing. The used component allows for an economical vehicle restoration while maintaining the factory character of the structure.

Before installation, it is recommended to always verify the condition of the edges, the working surface, and compatibility with the sealing system used in the specific vehicle unit.

Technical support and part selection

If you are planning a comprehensive repair or upgrade of the side glazing zone in your Mercedes and need other elements from the same group, such as door windows, rear side windows, or additional quarter glass, check the available parts in the Mercedes car windows category.

If you have any doubts regarding the choice of an aftermarket element or want to better understand the specifics of such products, it is worth reading the article Used car parts: Myths and facts you need to know, which explains the most common concerns regarding used components in an accessible way.

Additional information on the operation and care of dismantled parts, including body and glass components, is provided in the guide How to extend the life of used car parts?, which contains practical tips on maintenance and proper use.