G11, G12, G13 and G48 coolant explained

Confirm the specification in your owner’s manual before buying. Product examples are not a fitment guarantee.

G-designations at a glance

These are general descriptions used across the aftermarket. Formulations vary between suppliers, and vehicle makers publish their own spec numbers. Your manual is the authority.

Why the exact spec number matters

A bottle saying "G12" tells you the family, but each vehicle maker has its own specification number that coolants are tested and approved against. Coolant makers then print which specs their product meets or is approved for. Two "G12" products can have different approvals. When you buy, look for your manual's spec number on the label, as described in what coolant does my car need?.

G11 vs G12: what's the difference?

G11 contains silicate (a hybrid), while G12 is silicate-free organic acid (OAT). They protect metal by different mechanisms. Mixing them dilutes both packages, and some sources report that certain combinations can form deposits. If your car has G11 and you need G12 (or the reverse), the safe approach is a full flush and refill to the specified type. Check combinations below.

G12 vs G13: can you mix them?

G13 and G12++ are later Si-OAT evolutions. Some vehicle makers describe later grades as backward-compatible with certain earlier ones, but rules differ by maker and spec. Follow your manual or the carmaker's service information. If that isn't available, don't mix. Use the specified coolant, or drain and refill.

What is G48 coolant?

G48 is generally described as a silicate-containing hybrid (HOAT-type) coolant and is used by several European vehicle makers. As with every G-name, check that the label lists the spec your manual requires.

Premix or concentrate?

Most G-types are sold both ways. Concentrate is diluted, typically with distilled or deionized water, to the ratio on the label; 50/50 is common. Some ready-mixed G13 and G12 products are sold at other ratios, such as 40/60. See premix vs concentrate.

Reading VW/Audi-style spec names

Coolant names such as G12, G12+, G12++, G13 and G48 are commonly used to describe specific European coolant families. Bottles in the aftermarket may say "meets G13" or "suitable for TL 774-J". Specifications can be revised over time, so check that the product matches the exact spec your vehicle lists, not just the family name. If you're unsure, a dealer parts department can confirm the spec for your VIN.

G48 and similar silicate coolants

Silicate-containing hybrid coolants, often associated with the G48 name, are used by some European carmakers. They are a different family from the organic-acid G12-type coolants. Mixing them is generally not recommended. Use the type specified for your vehicle.

Topping up a European car on the road

1. Check the reservoir cap or manual for the spec.
2. Buy a premix that names the spec, if available.
3. If not, use distilled water to get home safely.
4. Restore the correct coolant soon and record it.

Common mistake

• Buying "G12" for a G13 car because the color looks similar. Specs differ. Match exactly.

G11 vs G48

The two names often appear together because they describe the same spec family from two directions. G11 is Volkswagen's name for coolant meeting VW TL 774-C. G48 is BASF's product name, and BASF lists GLYSANTIN G48 with the Volkswagen code G11 and approval TL 774-C. So for a VW Group car whose manual calls for G11, BASF presents G48 as a product that meets it. BASF also lists BMW and Mercedes-Benz approvals for G48 that the VW name does not cover.

Two cautions. BASF says not to mix G48 with its G64 because the two contain different inhibitors. Tesla also uses the name "G-48" for its own coolant: Tesla's service manual describes it as a phosphate- and nitrate-free ethylene glycol 50/50 premix. We found no source that says Tesla G-48 and BASF G48 are the same product, so match the exact name and part number in your manual.

Source: BASF GLYSANTIN: G48 Concentrate product page; BASF GLYSANTIN: approvals list; BASF GLYSANTIN FAQ: product selection and approvals; febi: Coolant G12evo product information (TL 774 letters); Tesla Model 3 (2024+) Service Manual: Fluids and Capacities.