Volkswagen has a history of using various coolant formulations in its vehicles, often leading to confusion about compatibility. This article focuses on G12evo, VW’s latest coolant, addressing its backward compatibility and potential concerns when mixed with older formulas.
Volkswagen initially used blue G11 coolant until around 1997, followed by the introduction of pink G12. However, G12 was not compatible with G11, causing sludge formation and cooling system issues if mixed. Subsequent formulations, G12+ and G12++, addressed this incompatibility issue and were used in Mk5 vehicles. G13, a purplish coolant, emerged in the mid-2010s, offering full backward compatibility.
G12evo, the current coolant offered by VW dealerships (with a specific exception for a 2015 TDI engine requiring G13), is also touted as backward compatible. While VW assures that mixing G12evo with older G-series coolants won’t cause functional problems, it acknowledges a potential color change to brown and a possible impact on long-term corrosion protection.
This brown discoloration raises concerns, especially for those familiar with the G11/G12 incompatibility issues. A real-world example involves a 2009 GLI where a partial coolant replacement with G12evo resulted in a brownish and slightly cloudy coolant mixture, noticeably different from the clear pink G12++ in a comparable 2009 Jetta.
While G12evo’s compatibility isn’t questioned, the color change suggests an incomplete flush and raises concerns about potential long-term corrosion. Should a full flush and refill with pure G12evo be performed to ensure optimal corrosion protection? While mixing is permissible, a complete flush might offer peace of mind and potentially prevent long-term issues. Sharing the cost of a full flush and new G12evo coolant with the repair shop could be a worthwhile investment.
In conclusion, G12evo represents VW’s latest coolant technology, designed for backward compatibility with previous formulations. However, mixing can result in a brown discoloration, raising questions about the thoroughness of flushing and the long-term impact on corrosion protection. A proactive approach, potentially involving a full flush and refill with G12evo, might be prudent to ensure optimal cooling system health.
