Have you ever stopped to think about coolant and what the colors mean? Getting the right coolant for your vehicle means you care about fluid maintenance and the impact of using quality products. The coolant aisle is one of the most diverse sections in an auto-parts store: jugs in green, orange, pink, yellow, blue, and purple, each labeled with cryptic codes (HT-12, IAT, OAT, HOAT, Dex-Cool, G40). The colors aren't decorative.
Instead, they signal the underlying chemistry, and mixing the wrong ones can cause damage. We can walk you through exactly what's in your engine and what products to put back in it.
Quick answer: Identify your coolant in 3 checks: (1) the owner's manual, (2) the color in the reservoir, and (3) the cap label. Match, don't mix, chemistries. When in doubt, choose a multi-vehicle formula compatible with your car manufacturer’s specifications.
How to Identify the Right Coolant in 3 Checks
It’s easy to use the right fluids in your vehicle. You can always find the answer in your manufacturer’s manual.
- Owner's manual. The most authoritative source. The maintenance section will list the OEM-recommended coolant by spec or part number.
- Reservoir color. Pop the hood and look at the overflow tank. The current color of the coolant is your first signal. This step isn’t foolproof, since some OEMs change dyes.
- Cap label. Many radiator and reservoir caps print the OEM coolant spec directly on the cap.
Coolant Color Chart
Each coolant varies by color. Once you know what those colors mean, it will be easier to choose the right coolant for your car. Some examples include:
IAT (Green) for Traditional Cars
Inorganic Acid Technology (IAT) is the classic green coolant used in older domestic vehicles (1990s and earlier). It has a short service life, typically 2 years or 30,000 miles. This coolant uses silicate and phosphate inhibitors that deplete relatively quickly.
OAT (Orange or Red) for Dex-Cool and G12 Vehicles
Organic Acid Technology (OAT) fluid has a long-life chemistry adopted by GM (Dex-Cool, orange) and some European makes (in the late 1990s). Service life is typically 5 years or 150,000 miles.
OAT (Orange) for Ford, Chrysler and GM
For Ford, Chrysler and General Motors vehicles that specify an orange extended life formula with Organic Acid Technology (OAT). Offers a typical service life of 5 years/150,000 miles.
HOAT G05 (Yellow) for some Ford and Chrysler
Low-silicate, reduced pH, phosphate-free formula with Hybrid Organic Acid Technology (HOAT). Used by Ford (yellow), Chrysler (yellow MS-9769), and several European OEMs, this type offers a typical service life of 5 years/150,000 miles.
Asian (Red) for Toyota and Lexus
For Toyota and Lexus vehicles that specify a red formula that’s silicate and borate-free with Hybrid Organic Acid Technology (HOAT). Zerex 5 year/150,000 mile guarantee protects against engine failure caused by freeze-ups or boil-overs.
Asian (Blue) for Honda, Nissan, Hyundai and Subaru
Silicate and borate-free with HOAT (Hybrid Organic Acid Technology). Specially formulated with a phosphate additive that protects from corrosion, scale and rust.
G40 (Pink) for Mercedes-Benz and other European makes
Premium carboxylate formulation recommended for Mercedes-Benz and (depending on the year of the vehicle) BMW, Porsche and VW cars and light trucks, as well as older Audi and Volvo vehicles. Specially formulated with state-of-the-art Si-Organic Acid Technology (Si-OAT).
HT-12 (Green or Pink) for Audi, BMW, MINI, VW, and Porsche
A premium coolant with state-of-the-art organic acid technology designed for vehicles requiring genuine HT-12 and G12evo fluid. Features a corrosion inhibitor package based on organic acids with modern stabilized silicate protection (Si-OAT).
Coolant by Make
| Make | Factory coolant | Recommended Valvoline product |
|---|---|---|
| Ford (older Ford (newer) | Yellow OAT Yellow HOAT G05 | ZEREX OAT or Multi-Vehicle ZEREX G05 or Multi-Vehicle |
| Chevrolet / GMC / Cadillac (1996+) | Orange OAT (Dex-Cool) | ZEREX Dex-Cool or Multi-Vehicle |
| Chrysler / Jeep | Purple OAT | ZEREX OAT or Multi-Vehicle |
| Toyota / Lexus / Scion | Pink Super Long Life | ZEREX Asian Vehicle |
| Honda / Acura | Blue Type 2 | ZEREX Asian Vehicle |
| Nissan / Infiniti | Blue | ZEREX Asian Vehicle |
| Subaru | Blue | ZEREX Asian Vehicle |
| BMW / MINI (newer) | Green HT-12 | ZEREX HT-12 Green |
| Volvo | Blue G48 | ZEREX G48 |
| Mercedes-Benz (older) | Blue G48 | ZEREX G48 |
| Mercedes-Benz (newer) | Pink/Violet G40 | ZEREX G40 |
| VW / Audi (newer) | Pink HT-12 | ZEREX HT-12 Pink |
| Hyundai / Kia | Blue/Green | ZEREX Asian Vehicle |
| Mazda | Green | ZEREX Asian Vehicle |
This table covers the most common North American applications.
Can you mix coolant colors or brands?
No. Mixing chemistries (IAT into OAT, for example) can cause corrosion inhibitors to precipitate from solution, gel the coolant, and clog small passages in the radiator and heater core. If you've accidentally mixed, the safest correction is a full system flush followed by a refill with the correct chemistry.
"Universal" or "multi-vehicle" coolants are formulated to be compatible with most color codes, but read the label carefully and confirm against your vehicle's spec.
Concentrate Vs 50/50 Prediluted
| Type | When to choose |
|---|---|
| Concentrate | Lower per-jug cost. Requires mixing with deionized or distilled water. Best for shops and DIYers handling multiple vehicles. |
| 50/50 Prediluted | Pour-and-go. No mixing. Best for the typical vehicle owner. |
How to Top Off Coolant
Checking your coolant should be a regular part of your vehicle maintenance. If the coolant is running low, top it off.
- Wait until the engine is cold. Never open a hot, pressurized cooling system.
- Open the overflow reservoir. Not the radiator cap. Most modern vehicles never require radiator-cap removal.
- Add coolant up to the COLD MAX line. Use the same chemistry/color that's already in the system.
- Re-cap and run the engine. Keep the car on until it reaches operating temperature, then re-check the level on the next cold start.
Frequently Asked Questions
Can I use water instead of coolant in an emergency?
Briefly, yes. Drain and refill with proper coolant as soon as possible. Water alone won't protect against freezing or corrosion and lowers the boil point.
How often should I change my coolant?
IAT (green): every 2 years/30,000 miles.
OAT/HOAT (long-life): every 5 years/100,000–150,000 miles.
ZEREX MaxLife is guaranteed for 400,000 miles when used as directed,* with up to 7X stronger protection against corrosion of aluminum compared to a leading conventional product.**
*Fluid guaranteed up to 400,000 miles under normal driving conditions when complete cooling system flush and fill is performed and proper maintenance is performed. Owner's manual recommendations must always be followed. (Valvoline approved claim — CLM-000008.)
**Based on aluminum corrosion protection vs. industry standard maximum. (Valvoline approved claim — CLM-000012.)
Is "universal" coolant safe to use in any vehicle?
Many modern multi-vehicle coolants are formulated to be compatible with the major chemistries, but compatibility is not always the same as OEM approval. Always verify against your owner's manual.
What's the difference between G48 and G12?
G48 is a low-silicate phosphate-free HOAT chemistry common in some older BMW, Volvo, and Mercedes. G12 is the VW/Audi pink OAT chemistry. They are not interchangeable.
The ZEREX Lineup: Finding the Right Match
Using the right coolant and not mixing types will help you avoid problems in your vehicle upkeep. Consult your owner’s manual or speak with a Valvoline expert to get it right the first time.
If you drive an older European vehicle that calls for a G48 coolant, choose ZEREX Green ZEREX G48 50/50 Prediluted. Drive a newer BMW, MINI or Audi, VW or Porsche? You may need a ZEREX coolant engineered specifically for European vehicles requiring genuine HT-12 and G12evo fluid.
For multi-vehicle households, ZEREX Multi-Vehicle 50/50 Prediluted may be what you’re looking for.
For the broadest selection across every chemistry, Asian Vehicle, Dex-Cool, Original Green, MaxLife, see the complete antifreeze coolant collection. For more on the difference between coolant and antifreeze, see Valvoline's primer on what antifreeze is.
