What Coolant Does My Car Need? (+Why Not to Go By Color)

You might have noticed a low coolant level in your car.
Or maybe the engine temperatures have been higher than usual, and you think a coolant flush is needed.

Your next question may be: What coolant does my car need?
Or: Should I use the same color coolant?

We can help you figure that out.
Let’s dive right in.

What Does Engine Coolant Do?

Engine coolant is a mixture of water and chemicals that prevents engine overheating or freezing in weather extremes. It’s also commonly referred to as radiator fluid or antifreeze. It keeps your engine cool through heat transfer—absorbing heat from the engine, where the hot coolant then dissipates heat at the radiator.

Your car coolant performs three vital functions:

It raises the cooling system’s boiling point in summer (so your coolant can better cool your engine as temperatures rise)

It lowers the cooling system’s freezing point in winter (so the coolant keeps flowing through your engine in freezing temperature)

It contains rust inhibitors to provide corrosion protection for your cooling system and engine

Coolant also indirectly helps heat your cabin. When you flip on the heater, hot coolant flows through the heater core. A fan then blows the heat from the heater core into the cabin through vents.

By the way, even electric vehicles use coolant, but to cool the battery, not the car engine.
Now, to find out what coolant your car requires.

What Coolant Does My Car Need?

The right coolant is critical in keeping your engine cool and preventing damage. If you need to change your coolant but don’t know which one to use, here’s what you can do:

Check the vehicle handbook first. It should tell what coolant you need (IAT, OAT, or something else) and may even define a brand.
If the manual has no brand recommendation, do some brand research.

A good coolant should have these features:

Has a high-quality formulation and certification meeting industry standards
Has a high boiling point with antifreeze properties to counter the effects of temperature extremes
Offers corrosion protection to prevent engine damage
Offers longevity to reduce change intervals

Consult an auto professional or your dealership. If you’re still unsure, you can always check with an expert technician or your car dealership for what coolant to use. Coolant is often branded for the car you use it in.

TIP: If you can’t get hold of an OE coolant, auto part stores also carry aftermarket options. These options will state that they work for specific brands or countries. The country a car is made in can help predict which aftermarket coolant it takes.

It’s obvious that radiator fluid doesn’t come in one size. Let’s explore the types so you have a better idea of what goes into your radiator.

What Are the Types of Engine Coolant?

These are the main types of car coolant you’ll find today:

1. IAT Coolant (Inorganic Additive Technology)

Inorganic Additive Technology coolant, which is green in color, has been used for decades. Older vehicles (possibly from 2001 and prior) will probably use IAT coolant. The base fluid is primarily ethylene glycol or propylene glycol with an inorganic corrosion inhibitor like silicates.

You’re less likely to find this coolant type in more recent vehicle models because its additives deplete faster, meaning it needs more frequent changing — typically every 2 years or 24,000 miles.

2. OAT Coolant (Organic Acid Technology)

Organic Acid Technology coolant is typically used in modern cars made by General Motors, Volkswagen, and some others. This coolant uses organic acids as the corrosion inhibitor and can come in several colors — usually orange, yellow, red, or purple. It’s not compatible with other types of coolant, and different colors shouldn’t be mixed as their silicate and phosphate composition can differ.

OAT coolant lasts longer than IAT coolant and should usually be changed every 5 years or 50,000 miles.

3. Hybrid OAT Coolant (Hybrid Organic Acid Technology)

Hybrid OAT (HOAT) coolant offers the benefits of traditional IAT coolant and modern OAT coolant. This coolant type has excellent protection from overheating while being available for use in many different vehicles, especially those with aluminum components.

HOAT coolant is usually orange or yellow and is commonly used in Chrysler and Ford vehicles. It typically requires change every 5 years or 50,000 miles, though some variations can last up to 10 years or 150,000 miles.

HOAT coolant can come as a few other subtypes, defined by their inhibitor technology, with different colors:

Phosphate-free HOAT coolant is usually turquoise
Phosphated HOAT (P-HOAT) coolant is generally pink or blue
Silicated HOAT (Si-OAT) coolant is purple

Knowing that coolant types come in different colors, let’s determine how much we can rely on color to select a coolant.

Does Coolant Color Matter?

While coolant color is a general indicator of type, you shouldn’t rely on color when getting fresh coolant. Remember, both OAT and HOAT coolants can be yellow or orange, which is misleading, and you could end up with the wrong coolant in your car engine.

Additionally, you shouldn’t refer to coolant used by vehicles from the same manufacturer, as they may very well use a different coolant to keep their engine block cool.

Your best bet is to check the vehicle handbook for the correct coolant type.

Have more questions on coolants?

5 FAQs on Coolants

Here are some common questions on coolant and their answers:

1. Is Antifreeze and Coolant the Same Thing?

The terms coolant and antifreeze are used interchangeably, but they aren’t exactly the same:

Antifreeze is an undiluted ethylene (or propylene) glycol-based liquid that prevents water from freezing. You must dilute it with distilled water before pouring it into your radiator.

Coolant is a mix of water and antifreeze, typically diluted 50:50.

2. Are Coolant Formulas the Same?

No. Though coolants are a blend of water and ethylene glycol (or propylene glycol), the additives can differ drastically from manufacturer to manufacturer. It’s important to always use the correct coolant type and follow instructions on the bottle. The wrong coolant could cause issues in your cooling system.

3. How Do Cars Lose Coolant? Do I Need to Top Up?

Older vehicles will lose more coolant than newer vehicles — as components begin to age and submit to wear and tear over time.

Your coolant can evaporate if the radiator cap is loose.

You can also lose coolant from leaks. A coolant leak may appear visibly under the car, such as when there’s a crack in the radiator hose or coolant reservoir. A coolant leak can also be less obvious, like when a leaking head gasket in your engine block allows coolant to enter the combustion chamber instead (and white smoke emits from the exhaust).

This is why it’s a good idea to check your coolant level regularly and top up if it’s low. Sticking to your car maintenance schedule and keeping an eye out for fluids under the car will help prevent major issues.

4. How Often Should I Change My Coolant?

It’s best to follow the schedule mentioned in the vehicle handbook, as different coolant types have different lifespans.

However, if you don’t have that to refer to, a general guide is to get a coolant change every 60,000 miles or 2-3 years.

5. Why Would My Car Need a Coolant Flush?

Coolant breaks down over time and becomes less effective. It can also become contaminated with rust, scale, and other debris. A coolant flush ensures that you have clean coolant in your car. It guarantees that you’re not mixing types or diluting the performance of the fresh coolant by mixing it with the old one.

Keep Your Car Cool with AutoNation Mobile Service

Coolant is as vital as engine oil, playing a crucial role in keeping your engine cool. Changing your coolant at the correct intervals helps prevent bigger issues like engine overheating, and it’s important that you use the right coolant. Here, the vehicle handbook is your best reference.

If you need help with your coolant — whether to change it or advise on which type to use — you can always rely on AutoNation Mobile Service.

We’re a mobile car maintenance and repair service. We’re available 7 days a week and can handle your car repair or maintenance right from your driveway. Schedule an appointment with us, and our best mechanics will drop by to lend a hand.