G13 Coolant Related Problems — Story of a Complex Diagnostic Case

G13 Coolant and the Mysterious Series of Failures

The problem began when the car was continuously regenerating and the diesel particulate filter (DPF) was constantly saturated. Initially, we looked for the fault in the injectors, as the engine was smoking. This was the beginning of a long and expensive ordeal that eventually led to the conclusion that the G13 specification coolant used in VW group vehicles (Audi, Volkswagen, Škoda, Seat) can cause serious problems in the cooling system under certain circumstances.

It is known that the VW group has since replaced this coolant, creating the G12 EVO. Many problems occurred and recall campaigns were carried out. There were continuous recalls in Škoda and VW cars due to the silicate bag, which had punctured, and the silicate balls inside clogged the cooling system. Over the years, continuous problems arose with various radiators, seals, and other elements.

This case study is instructive not only because it highlights certain problems with G13 coolant, but because it demonstrates how often it occurs in auto repair shops that individual parts failures are treated as isolated cases without revealing the underlying, system-level problem. Instead of thorough diagnostics, the "replace what's broken" approach resulted in unnecessary expenses of several hundred thousand forints – which could have been avoided from the beginning with a properly perspective professional.

Special Properties and Risks of G13 Coolant

Before detailing the specific problems, it's important to understand what G13 coolant is and why it can cause special problems:

• Advanced technology: G13 (purple in color) is an organic acid technology (OAT) coolant introduced by the VW group
• Environmentally friendly formula: It does not contain phosphates and nitrites, making it more environmentally friendly
• Longer lifespan: In theory, it provides a longer replacement interval (up to 4-5 years)
• Chemical sensitivity: Particularly sensitive to mixing with other types of coolants
• Sealing characteristics: Behaves differently with rubber seals than traditional coolants

The fundamental problem with G13 coolant is not in its quality, but in its chemical properties and interaction with other elements of the system. G13 is prone to:

1. Dissolve certain types of materials used in seals
2. Change viscosity over time, which can affect the flow characteristics of the cooling system
3. React with certain metals, especially if air enters the system
4. Form deposits in the narrower cross-sections of the cooling system

These properties are not problematic in themselves if all elements of the cooling system are functioning perfectly. However, a small leak, a minor design flaw, or improper maintenance can trigger a chain reaction, as we will see in the following chapters.

The Series of Parts Problems and Misdiagnoses by Service Centers