Vaico V10-0556 Engine Coolant Reservoir

Engine Coolant Reservoir for Audi and Volkswagen

The Vaico V10-0556 engine coolant reservoir is an OE-style replacement tank for select Audi and Volkswagen applications. Built to match OE number 8D0 121 403 L, it supports proper coolant expansion and recovery in vehicles such as the Audi A4, A6, RS6, Allroad Quattro, and Volkswagen Passat.

VAICO focuses on application-specific replacement parts, and this reservoir follows the original equipment reference for a direct-fit service part. The V10-0556 is sized to match the factory layout and is listed for multiple B5/B6-era Audi and Passat cooling system applications.

Key Features

• OE reference: 8D0 121 403 L
• Engine coolant reservoir for cooling system service
• Dimensions: 305 mm length, 240 mm width, 140 mm height
• Weight: 0.600 kg
• Aftermarket replacement for select Audi and Volkswagen models
• Cross-references OE numbers 8D0 121 403 F and 8D0 121 403 J for the same application

Detailed Description

Vaico V10-0556 is an engine coolant reservoir designed around OE number 8D0 121 403 L for accurate fitment on select Audi A4, A4 Quattro, A6, A6 Quattro, RS6, Allroad Quattro, and Volkswagen Passat vehicles. The reservoir’s listed dimensions and OE match help maintain the original cooling system layout, making it a practical replacement when the factory tank is cracked, leaking, or no longer holding pressure correctly. This part number, V10-0556, is a direct reference for buyers searching by OE number or by vehicle application.

Common Reasons for Replacement

• Coolant loss from a cracked or aging reservoir
• Visible staining, warping, or seam damage on the tank
• Low coolant warnings caused by reservoir leakage
• Pressure loss in the cooling system from a damaged expansion tank
• Service replacement for an OE-number-matched cooling component

Installation Notes and Tips

Verify the OE number on the original reservoir before ordering, especially on 1998-2005 Audi A4, A4 Quattro, A6, A6 Quattro, 2003-2005 Audi Allroad Quattro, 2003-2004 Audi RS6, and 1998-2005 Volkswagen Passat applications. Fitment notes include VIN breakpoints for some Audi A4 and A6 models, so confirm the vehicle build date and VIN range against the listing. Inspect hoses, caps, and seals during replacement to ensure the cooling system is restored correctly.

Quality Assurance

VAICO supplies application-specific aftermarket parts built to OE reference standards. This reservoir is identified for OE number 8D0 121 403 L and is cataloged for direct replacement use on the listed Audi and Volkswagen cooling system applications.