2021-2022 Audi Coolant Mixing Guidelines TSB 2025303

This Technical Service Bulletin (TSB 2025303/12) addresses the critical topic of identifying and correctly mixing factory-fill engine coolants in 2021-2022 Audi vehicles, including the Audi e-tron coolant mixing. Issued on January 10, 2022, this bulletin supersedes an earlier version (Group 19 number 20-04, dated June 25, 2020) to provide updated information and procedures.

Modern combustion engines place high demands on their cooling systems. Audi continuously develops its coolants to meet these evolving requirements, ensuring optimal engine performance and longevity.

Why Correct Coolant Matters

Audi has progressively replaced older coolant types like G11, G12, and G12+ with improved versions over the years. G12++ coolant was introduced in Model Year (MY) 2005, followed by G13 in MY 2008 as the initial fill and service coolant. More recently, G12evo was introduced in MY19.

Using the correct coolant and avoiding improper mixing is essential for maintaining the integrity of your vehicle's cooling system. Incorrect coolant types or mixtures can lead to reduced corrosion protection and potential damage.

Identifying Your Coolant Type

The first step in managing your Audi's coolant is to identify the type currently in your vehicle. Factory-fill coolants can often be identified by their color. For instance, G11 is green-blue, G12 is red, while G12+, G12++, G13, and G12evo are all purple.

Understanding the specific type of coolant originally installed in your vehicle is the first step in preventing issues related to Audi e-tron coolant mixing or any other Audi model. Technicians use visual identification (referencing Figure 1 in the original document) to determine the factory-fill coolant.

Coolant Mixing Compatibility Chart

Once the factory-fill coolant is identified, technicians consult a compatibility chart to determine which service coolants can be added. This chart (Figure 2 in the original document) outlines the mixing ratios and potential effects.

Here's a summary of the mixing compatibility:

Can be mixed with:	Green-blue G11 (≥ 1994)	Red G12 (≥ 1996)	Purple G12+ (≥ 2000)	Purple G12++ (≥ 2005)	Purple G13 (≥ 2012)	Purple G12evo (≥ 2018)
G11	Green	Red	Red	Red	Red	Red
G12	Red	Green	Yellow	Yellow	Yellow	Yellow
G12+	Red	Yellow	Green	Green	Green	Green
G12++	Red	Yellow	Green	Green	Green	Green
G13	Red	Yellow	Green	Green	Green	Green
G12evo	Red	Yellow	Green	Green	Green	Green

• Green: Indicates that the coolants can be mixed in any ratio without issue.
• Yellow: Indicates that mixing is possible, but it will result in a reduction of corrosion protection.
• Red: Indicates that the coolants cannot be mixed under any circumstances.

Important Warnings and Considerations

Audi has specific guidelines regarding coolant handling and mixing that owners and technicians must observe:

• Warranty Coverage: Cooling system drain and fill procedures performed due to coolant mixing or the use of incorrect coolant are not covered by Warranty.
• Water Type: Only mix distilled water with coolant additives as specified in ElsaPro procedures. Deionized water must not be used.
• Drained Coolant: Drained coolant must not be reused.
• Color Change: If G11 coolant is mixed with G12+, G12++, G13, or G12evo, the coolant will turn brown. This is considered normal and not an indication of a problem.
• Best Practice: While some coolants can be mixed, it is always best practice to change the entire coolant if there's any doubt about compatibility or if reduced corrosion protection is a concern. It is crucial to adhere to these guidelines to prevent issues like reduced corrosion protection or cooling system damage, which are common concerns with improper Audi e-tron coolant mixing.

Repair Procedure Summary

If an incorrect coolant is found in the system, or if mixing is necessary and compatibility is a concern, the cooling system should be drained and refilled. The procedure involves:

1. Draining the cooling system according to the Repair Manual procedures in ElsaPro.
2. Refilling the system with water.
3. Running the engine for 15 minutes with the heater on to remove any residual coolant.
4. Draining the system again and refilling it with the correct coolant to the specified freeze protection ratio, as detailed in ElsaPro.

For measuring freeze protection, a refractor like the T10007B is used for G12evo coolant. If the coolant type (G12, G13, or a mixture) is unclear, the G13 scale of refractors T10007A/B should be used.

Required Tools and Parts

Technicians will use specific Audi-approved coolants and tools:

• G12evo coolant: Part number G-12E-050-1G-DSP (for MY 2019 and newer vehicles, including the Audi e-tron).
• G13 coolant: Part number G-A13-774-1G-DSP (for MY 2018 and older vehicles).
• Refractors: T10007B (for G12evo) and T10007A/B (for G13 and general use).
• ElsaPro: Audi's workshop information system, which provides detailed repair manuals and procedures.

Always check with your Parts Department or ETKA for the latest information on parts and service references, as these are subject to change.

Owner Action

If you are unsure about the type of coolant in your 2021-2022 Audi or have concerns about coolant mixing, it is recommended to consult an authorized Audi service center. They can accurately identify the coolant and perform any necessary service according to Audi's guidelines.

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NHTSA ID: 10207170