Volkswagen and Audi vehicles require specific coolants for optimal performance and longevity. This article explores the evolution of VW/Audi coolants, focusing on G12 evo coolant and its compatibility with previous formulations. Understanding these nuances can help ensure your vehicle’s cooling system remains in top condition.
A History of VW/Audi Coolants: From G11 to G12 Evo
VW/Audi has a history of developing specialized coolants. Initially, they used the blue-colored G11 until around 1997. This was followed by the pink G12, which was notably not backward compatible with G11. Mixing these two coolants resulted in a sludge that could damage the cooling system. Neither of these coolants were compatible with conventional green coolants available at the time.
Subsequent formulations, G12+ and G12++, addressed the compatibility issue, allowing for mixing with G11. Most Mk5 vehicles were factory-filled with either G12+ or G12++. In the mid-2010s, the purplish G13 was introduced, maintaining backward compatibility with all previous versions.
The latest coolant, G12 evo, is the current standard for VW/Audi vehicles (with a single exception for a specific 2015 TDI engine requiring G13). While G12 evo is backward compatible with older G-series coolants, mixing can result in a brown discoloration. Although VW/Audi assures this doesn’t compromise functionality, it raises concerns about potential long-term corrosion protection.
The image above shows a comparison between fresh G12++ (bottom) and a mixture of G12++ and G12 evo (top). The brownish tint and cloudiness in the mixed coolant are evident.
G12 Evo Compatibility Concerns: A Real-World Example
A 2009 GLI, originally filled with G12++, had its coolant partially replaced with G12 evo during a repair. Despite a supposed flush, the resulting coolant mixture exhibited a brownish color and cloudiness, as seen in the image below. This raises questions about the thoroughness of the flushing process and the potential long-term effects on corrosion protection.
While mixing G12 evo with older coolants is officially permissible, the color change can be unsettling, especially for those familiar with the sludge issues caused by mixing G11 and G12. The uncertainty surrounding long-term corrosion protection warrants consideration.
Ensuring Optimal Cooling System Performance with G12 Evo
While G12 evo offers backward compatibility, a complete flush and refill with pure G12 evo is recommended when transitioning from an older coolant. This ensures the full benefits of G12 evo and minimizes potential long-term risks. Although mixing is technically allowed, a complete coolant replacement offers peace of mind and optimal corrosion protection. Consult your service professional for guidance on the best approach for your specific VW or Audi vehicle.
