What Coolant a 2018 Audi A4 Uses — And Why It Matters

A 2018 Audi A4 is designed to use OEM Volkswagen/Audi–approved G13 (purple/violet) coolant or its current superseding equivalent from Audi, always mixed with distilled water to about a 50/50 ratio, and never mixed with generic green or universal coolant. This specialized, silicate-containing, OAT-based coolant protects the aluminum engine and cooling system from corrosion and overheating.

The Basics: Official Coolant Specification for a 2018 Audi A4

The 2018 Audi A4 shares its coolant requirements with many late‑model Volkswagen Group vehicles. Audi specifies a long‑life, phosphate‑free coolant that meets its internal VW/Audi standards rather than a generic automotive antifreeze. This is critical both for engine longevity and to avoid costly cooling‑system damage.

Official Audi/VW Coolant Type and Color

The 2018 Audi A4 typically uses G13 coolant as supplied by Audi dealers. G13 was introduced as an update to the earlier G12++ coolant, and in practice, many Audi dealers now stock the latest superseding formulation, which remains backward‑compatible. While the formula can evolve, the approval code on the bottle is what really matters.

The key factory specs for a 2018 Audi A4 coolant are:

• Type: VW/Audi G13 (or updated equivalent) long‑life coolant
• Specification: Must meet VW TL 774 J (G13) or the current Audi/VW–approved standard listed in your owner’s manual
• Typical color: Purple, violet, or pinkish‑purple from the factory
• Base chemistry: OAT (Organic Acid Technology) with glycerin, silicate‑containing, phosphate‑free
• Mixture: Commonly 50% coolant concentrate and 50% distilled water (down to about –35°C / –31°F)
• Branding: Sold as Audi/VW Genuine Coolant/Antifreeze at dealerships; reputable aftermarket brands also offer “VW G13 / TL 774 J–approved” coolant

These points mean that, while color is a useful quick check, the decisive factor is the VW/Audi approval printed on the label and not generic “compatible with all makes” claims.

G12 vs. G13: What If You See Different Labels?

Depending on region and supply, you may see coolants marketed as G12++, G13, or a newer, dealer‑only formula that replaces them. All are intended to be backward compatible when they carry the correct VW approval number. For a 2018 A4, G13 or its officially superseding formula is typically what the dealer will use.

When in doubt, the coolant bottle should explicitly state that it meets the applicable VW/Audi coolant standard for your car’s year and model, rather than just matching the color or marketing name.

How to Check the Correct Coolant for Your Specific 2018 Audi A4

While G13 (or its official successor) is the general rule for a 2018 A4, it is always wise to confirm the exact specification for your particular engine code and market. Minor regional variations or running changes can occur over a model’s lifecycle.

Here are practical ways to verify the correct coolant type for your exact vehicle:

1. Consult the owner’s manual: The cooling system section will specify the VW/Audi coolant standard (e.g., VW TL 774 J, G13) and mixing ratio.
2. Check the coolant expansion tank cap or sticker: Many Audi models have a note indicating the required VW coolant spec.
3. Call an Audi dealer with your VIN: Service staff can look up your A4’s build data and confirm the factory coolant requirement.
4. Review service records: Previous dealer invoices often list the exact coolant product used.
5. Use only VW/Audi–approved products: If buying aftermarket, confirm the label explicitly states compliance with the relevant VW TL 774 standard for your model year.

By tying the coolant choice to official documentation or VIN‑linked dealer data, you avoid relying on color or generic cross‑reference charts that may be inaccurate or overly broad.

Why You Should Not Use Generic or “Universal” Coolant

Modern Audi engines rely on a specific coolant chemistry that protects aluminum components, prevents internal corrosion, and is compatible with seals and plastics. Using the wrong coolant can trigger several long‑term problems that may not be immediately obvious but are expensive to fix.

The main risks of using non‑approved or mixed coolants include:

• Corrosion and pitting: Incompatible additives can fail to protect aluminum heads, radiators, and heater cores, causing internal damage.
• Sludge and gel formation: Mixing G13 with older “green” or universal coolants may cause gel‑like deposits that restrict cooling passages.
• Water pump and seal damage: Incorrect additive packages can shorten water pump life and lead to leaks.
• Overheating and poor heat transfer: Deposits and corrosion reduce cooling efficiency, raising engine temperatures and stress.
• Warranty or goodwill issues: For vehicles still under extended coverage, non‑spec coolant may complicate future claims.

Because these failures often emerge gradually, adhering to the factory‑approved coolant is a low‑cost way to protect a costly engine and turbo system over time.

Mixing, Topping Off, and Concentration for a 2018 Audi A4

In normal use, a 2018 Audi A4’s coolant is long‑life and does not require frequent replacement, but small losses can occur over time. Topping off incorrectly is one of the most common owner mistakes.

Proper Coolant Mixture Ratios

Audi typically recommends a mixture of concentrated coolant and distilled water tailored to both freeze and boil‑over protection. A balanced mix also maintains the additive chemistry as designed.

Typical, widely accepted mixing guidelines are:

• 50% coolant / 50% distilled water: Standard mix for most climates; protection to roughly –35°C (–31°F).
• 60% coolant / 40% distilled water: For extremely cold climates; improves freeze protection but should not be exceeded.
• Never use 100% concentrate: Pure antifreeze actually transfers heat worse and can reduce cooling efficiency.
• Use distilled or de‑ionized water only: Tap water can introduce minerals that lead to scale and deposits.

Following the recommended ratio preserves both thermal performance and corrosion protection, which is especially vital in a turbocharged engine under high load.

Safe Practices When Topping Off Coolant

When the coolant level drops slightly, adding fluid might seem straightforward, but a few rules help prevent damage or contamination of the system.

Key topping‑off guidelines include:

1. Check level when engine is cold: A hot system is under pressure and can spray scalding coolant if opened.
2. Use the same spec coolant already in the system: Ideally, top off with the exact VW/Audi G13 (or equivalent) product used previously.
3. If in doubt, use premixed G13/distilled water: Many dealers sell ready‑to‑use mixture at the correct ratio.
4. Do not overfill: Fill only to the “MAX” mark on the expansion tank to allow for thermal expansion.
5. Investigate regular losses: If the level keeps dropping, have the car inspected for leaks or other issues.

Consistent topping off with the correct, approved fluid maintains the integrity of the factory coolant chemistry and helps avoid expensive repairs later on.

When and How Often Coolant Should Be Changed

Audi’s long‑life coolant is designed to last many years, but it is not permanent. Over time, the corrosion inhibitors degrade, especially under harsh driving conditions or if the system has been opened for repairs.

Typical service considerations for a 2018 Audi A4 include:

• Service interval: Audi often treats coolant as “lifetime” under normal conditions, but many independent specialists recommend replacement around 8–10 years or 150,000–160,000 km (about 90,000–100,000 miles), or when major cooling work is done.
• Condition‑based changes: If coolant looks rusty, brown, cloudy, or contaminated, it should be flushed and replaced regardless of mileage.
• Post‑repair replacement: Major cooling‑system jobs (water pump, radiator, heater core, etc.) are a good time to renew the coolant.
• Professional bleeding: The A4’s system may require proper bleeding procedures to remove air pockets, especially on turbo and heater circuits.

Using the correct new coolant at replacement time is just as important as choosing the right oil—both are critical lifelines for a modern engine.

Buying the Right Coolant for a 2018 Audi A4

For owners purchasing coolant themselves, the market can be confusing, with multiple colors and claims of universal compatibility. A methodical approach helps avoid costly mistakes.

When sourcing coolant for your 2018 Audi A4, consider these steps:

1. Prefer genuine Audi/VW coolant: Buy directly from a dealer or a trusted parts supplier listing it as OEM.
2. Check specification, not just “G13” wording: Ensure the label explicitly states it meets the applicable VW TL 774 standard for your car.
3. Avoid “all makes, all models” green coolant: These often lack the correct additive package for VW/Audi systems.
4. Match concentrate vs. premix to your needs: Premix is safer for quick top‑offs; concentrate offers flexibility if you have distilled water and need a full flush.
5. Buy from reputable brands: Major European‑focused coolant manufacturers often sell VW‑approved G13‑type products, but always verify the approval code.

By focusing on the official VW/Audi approval, you cut through marketing noise and ensure your coolant truly matches what the engineers specified for the 2018 A4’s cooling system.

Summary

A 2018 Audi A4 is engineered to use VW/Audi‑approved long‑life coolant, specifically G13 (purple/violet) or its officially superseding equivalent, mixed about 50/50 with distilled water. The crucial factor is that the coolant meets the appropriate VW TL 774 standard listed in the owner’s manual or confirmed by an Audi dealer, not just that it is the right color or promised to be “universal.”

Sticking to this OEM‑spec coolant, avoiding mixing with generic green antifreeze, and topping off only with the correct product at the proper concentration together help protect the turbocharged engine, water pump, radiator, and heater core from corrosion, overheating, and premature failure over the long life of the car.

What coolant does the Audi A4 use?

Pentosin – Pentofrost NF (G11) Silicate European Concentrate Antifreeze / Coolant – 1.5 Liters (Part No. 8114117)

What coolant does a 2018 Audi A4 use?

2018 Audi A4 Quattro. Notes: Coolant / Antifreeze – Audi/VW G13 (Lilac) (5 Liter) — Compatible with all colors of Audi/VW coolant / antifreeze.; Concentrate. For distilled water, see part # 55 7864 010.

What happens if I put all-purpose coolant in an Audi?

If you use the incorrect coolant in your Audi then lots of issues may arise. Corrosion and water pump damage, seal damage, radiator damage and much more lead to costly repairs.

Does Audi need special coolant?

But unlike generic vehicles, Audi coolant is different. It’s specially formulated to work with Audi’s aluminum engine components and precision-engineered cooling systems.