Audi Q7 4L Adblue Additive Reservoir Tank 3.0 TDI Diesel 4L0131878D

Visual condition of the part

The product shows signs of use visible in the photos.

Audi Q7 4L Adblue Additive Reservoir Tank 3.0 TDI Diesel is a fuel supply system component designed for diesel vehicles, responsible for storing the AdBlue solution that works with the exhaust emission reduction system. Thanks to a design consistent with Audi factory solutions, the tank ensures proper cooperation with the SCR system and the vehicle's electronics. It is a practical choice for users who want to restore full efficiency to the exhaust treatment system in their Q7 3.0 TDI.

Specifications and technical data

• SKU: 4L0131878D
• Mark: Audi
• Condition: Used
• OEM Part Number: 4L0131878D
• Substitutable numbers: 4L0131878D, 4L0 131 878 D, 4L0 131 878 H, 4L0131878H, 4L0131899G, 4L0 131 899 G
• Fuel type: Diesel
• Part type: Fuel Tank
• Category: Fuel Tanks & Filler Necks

Purpose and function in the AdBlue system

The presented tank is part of the Fuel tanks and filler pipes group, however, in this case, it is responsible for the safe storage of the AdBlue solution in a diesel vehicle. Its task is to provide a stable supply to the dosing system so that the SCR system can effectively reduce nitrogen oxides in the exhaust gases. A properly selected tank minimizes the risk of engine control unit errors, AdBlue system fault messages, and starting problems resulting from the inability to dose the solution.

Compatibility and selection by part numbers

The element has been designed for the Audi Q7 4L platform with a 3.0 TDI unit, which means it fits factory mounting points and works with the original fuel and emission system. The tank has a dedicated OEM part number and associated interchangeable numbers, which facilitates precise identification and selection via a catalog or VIN number. This allows you to verify compatibility with a specific equipment version and vehicle year, reducing the risk of purchasing a non-matching component.

Technical and operational characteristics

As an element intended for vehicles with a diesel engine, the AdBlue tank is adapted to operate in variable temperature conditions and to work with the urea solution injection system. The design provides appropriate connection ports and space for accessories (such as level sensors or AdBlue supply system components, if provided in the given vehicle configuration). The use of the original geometry facilitates installation in the factory location, without the need for modifications to the installation or brackets.

The used condition means that the element comes from disassembly, which in practice allows you to combine a favorable price with the preservation of the manufacturer's original specifications. Before installation, it is recommended to perform a standard check of tightness, the condition of the ports, and any seals to ensure trouble-free operation after installation in the vehicle.

Benefits of using an original AdBlue tank

Using a factory AdBlue tank in an Audi Q7 4L brings a number of practical advantages:

• maintaining compatibility with the factory SCR system and engine controller,
• proper cooperation with the hose installation and body mounts,
• reducing the risk of leaks and system errors resulting from mismatched replacements,
• easier diagnostics at the service center thanks to the preservation of the original system architecture.

For users who want to maintain the efficiency of the emission reduction system and avoid problems with the limp mode, choosing such a component is a technically safe and predictable solution in operation.

Installation area and related components

The AdBlue tank is integrated with the fuel supply and exhaust treatment area, working with the hoses supplying the solution to the dosing module and with sensors monitoring the level and temperature of the medium (if present in the given configuration). During replacement, it is worth paying attention to the condition of the hoses, connectors, and mounts to avoid stress and leaks after installation. A properly installed tank supports the stable operation of the fuel and emission system, which translates into the correct operation of the diesel engine across the full load range.

If you are planning a comprehensive repair or upgrade of the fuel supply and storage area in your Audi and need other elements from the same group, such as additional tanks, filler pipes, or mounting elements, check the available parts in the Audi fuel tanks and filler pipes category.

To better understand the role of the tank in the entire supply path and the relationships between it, pumps, and injectors, it is worth referring to the service manual describing the diagnostics and operation of the fuel system – you will find it in the article Fuel system – injectors, pumps, and fuel tank: maintenance and regeneration.