How to find the right coolant for your car

What is Coolant?

The styling of modern cars means engines don’t often have a lot of space. This can lead to overheating as the heat the engine generates is confined in a small space with no room to disperse. In this circumstance, a high-functioning cooling system is essential to prevent overheating.

Coolant is a fluid that circulates through your car’s cooling system. Most coolant is a mixture of an anti-freeze anti-boil corrosion inhibitor concentrate that has been diluted 50/50 with distilled water. This fluid is able to keep your car cool by absorbing heat from the engine and releasing it through the radiator.

Using the wrong coolant for your car could be ineffective and result in a damaged engine.

Why is engine coolant important?

Coolant performs three main functions to protect your car engine:

  1. Coolant transfers heat from the engine and releases it through the radiator, keeping the engine at a safe operating temperature.
  2. Coolant generally has a higher boiling point and a lower freezing point than plain water.
    -If the water in the engine boils, it turns into a gas, which cannot transfer heat effectively.
    -If the liquid in the cooling system were to freeze, it would expand, potentially damaging parts of the cooling system and the engine.
  3. The same coolant contains corrosion inhibitors that protect the metallic and non-metallic (rubber hoses, seals, plastic tanks, etc.) parts of the engine cooling system.

Why use coolant and not just water?

There are two key advantages of using engine coolant rather than just water.

First, coolant has a higher boiling point than water. This means that when parts of the engine heat to over 100°C, the coolant liquid won’t boil.

The second key reason to use coolant is that coolant contains corrosion inhibitors. This protects the components of your engine and cooling system from corrosion. It’s much cheaper to buy coolant and check it regularly than it is to replace major parts of your car engine and cooling system.

What are the different types of car coolant?

There are 2 main different types of car coolant available.

  • Anti-freeze/anti-boil (AFAB) Australian Standard AS2108-2004 “Type A” Coolant. This comes in various special formulations for particular uses:
    • Organic Acid Technology (OAT) premium AFAB coolant for general use
    • Hybrid Additive Technology (HAT) AFAB coolant for general use
    • Phosphate-based AFAB coolant (formulated for Japanese & Korean car makes)
    • Silicate-based AFAB coolant (formulated for European car makes)
  • Corrosion inhibitor (CRIN) Australian Standard AS2108-2004 “Type B” Coolant. This comes in various special formulations for particular uses as well.
    • Regular formulation
    • Organic Acid Technology (OAT) premium corrosion inhibitor for general use

What’s the right coolant for my car?

car and radiator coolant

Always check your car manual to ensure the coolant you choose meets the requirements of the manufacturer.

What’s the right coolant for Honda, Hyundai, Kia, Mazda, Mitsubishi, Nissan, Subaru or Suzuki?

For these car models, we recommend using Adrad’s AFAB blue phosphate-based coolant designed for Japanese and Korean vehicles.

What’s the right coolant for Toyota or Lexus?

If you drive a Toyota or Lexus, we recommend choosing Adrad’s AFAB pink phosphate-based coolant designed for Japanese vehicles.

What’s the right coolant for Ford?

If you drive a Ford built in 1997 or later, we recommend choosing Adrad’s orange organic CRIN coolant, or using Adrad’s orange organic AFAB coolant if your car may be exposed to freezing temperatures.

Adrad’s green inorganic CRIN or AFAB coolants can be used in Fords built before 1997.

What’s the right coolant for Holden?

If you drive a Holden that was built after 2001 and is either a turbocharged, Alloytec, V8 Gen III or IV model: use Adrad’s orange organic CRIN or orange organic AFAB coolant, depending on the climate where the car is used.

If your Holden was built before 2001 and isn’t either a turbocharged, Alloytec, V8 Gen III or IV model: use Adrad’s green inorganic CRIN or Adrad’s green inorganic additive technology AFAB coolant.

What’s the right coolant for Mercedes, VW or Audi?

Many European cars built after 2004 require organic AFAB coolant (orange coloured). However, from 2008 onwards, some Audi and VW models require a special European standard, silicate enhanced AFAB coolant (purple coloured).

Older European models can use Adrad’s orange organic AFAB or their orange organic CRIN coolant, if the car isn’t exposed to freezing temperatures.

If you still aren’t sure which coolant you should select for your car, a radiator technician at your nearest Natrad store can give you advice on choosing the right coolant.

How do I top up my car coolant?

pouring coolant into tank

Now that you know which coolant to put into your car, here’s a video guide explaining how to top up your car’s coolant.

You can purchase coolant as either concentrate (which requires mixing with distilled water) or buy coolant pre-mixed (which can be poured directly into the radiator).

Now we’ve covered the basics, here is a more comprehensive guide to the different types of engine coolant:

Features of Type A AFAB Coolant:

Adrad’s organic AFAB coolant is coloured orange. Inorganic coolant can be purchased for older vehicles and is coloured green. Most modern cars require organic anti-freeze coolant.


Adrad’s AFAB coolant, supplied by Natrad, provides wide temperature protection. A 50/50 mixture will protect your engine at temperatures from -37 °C to 129 °C.


This coolant provides protection against pitting, corrosion and erosion of aluminium, iron, steel, brass, copper and solder alloys. Adrad’s organic (orange) coolants are phosphate-free, which means that there will be less hard-water scale build-up. By reducing the concentration of dissolved solids from hard water, using this coolant will increase the longevity of water pump seals.


Adrad’s organic (orange) coolants are free from nitrite, nitrate, amine, phosphate, silicate and heavy metals such as borate.


Adrad premium organic (orange) AFAB Type A coolant is designed to last up to 250,000 km or 8 years for passenger cars.


Both Adrad’s organic and inorganic AFAB coolant (orange and green, respectively) meets AS 2108-2004 for engine coolant Type A.


If your vehicle is built after 2001, select an organic AFAB (orange) coolant. Any vehicle with a turbo/supercharged engine, Holden Alloytec, or Gen III or IV V8 should also use orange organic coolant, rather than the cheaper, green inorganic AFAB coolant.

AFAB should be used in any car that could be exposed to freezing temperatures.

Features of Type B CRIN Coolant:

Adrad’s organic CRIN or Type B coolant is coloured orange. The inorganic version of this coolant is coloured green. This water-based mixture is suitable for a wide range of cars where freeze protection is not required.


This coolant provides cost-effective engine protection where anti-freeze is not required.


Adrad’s CRIN coolant provides stable and reliable protection from pitting, corrosion and erosion for metals, including aluminium, iron, steel, brass, copper and solder alloys.

The formula in this coolant doesn’t contribute to deposit build-up, which can restrict and block the radiator system. It provides protection for rubber and plastic parts of the engine and cooling system.


Adrad’s organic CRIN (orange) coolant is free from nitrites, nitrates, amines, phosphates and silicates (NAPS-free), as required by numerous car manufacturers. This coolant is free from borate and other heavy metals.


Adrad’s premium organic CRIN Type B (orange) coolant is designed to last up to 250,000 km or 8 years in passenger cars.


Both Adrad’s organic and inorganic CRIN coolant (orange and green, respectively) meets AS 2108-2004 Engine Coolant Type B and Ford Engineering Specifications.


This water-based coolant is suitable for vehicles in warm climates, where anti-freeze isn’t required. It can be used in cars, tractors, on or off-highway trucks and marine applications. Choose an orange organic CRIN coolant for vehicles built since 2001.

Features of Si-OAT coolant:

Adrad’s Silicate-Enhanced Organic Additive Technology (Si-OAT) anti-freeze coolant is based on ethylene glycol and glycerol and contains a durable OAT inhibitor combined with silicate additives (Si-OAT).

This purple-coloured coolant is used in the latest high-tech European engines where high-temperature aluminium protection is required.


Designed to meet the specifications of modern European vehicle manufacturers, Adrad’s Si-OAT coolant provides effective anti-freeze and anti-boil protection, particularly for aluminium components.


This high-performance conventional coolant provides effective corrosion protection for all engine metals, including aluminium and ferrous alloys. It can be used with confidence in engines manufactured from cast iron, aluminium or combinations of these two metals, and in cooling systems made from aluminium or copper alloys.

Adrad’s Si-OAT coolant provides excellent corrosion, cavitation and erosion protection for aluminium water pumps.


Silicon-enhanced coolant uses a more environmentally friendly manufacturing process, partially replacing ethylene glycol with glycerol.


Adrad’s Silicon-enhanced coolant is compatible with most other coolants based on ethylene glycol. The cooling system should be flushed and coolant replaced every 250,000 km or 5 years.


Natrad supplies Adrad’s silicon-enhanced coolant which meets or exceeds: AS 2108-2004 Type A, ASTM D3306, BS 6580:2010, G11/G12/G12+/G12++, VW TL 774 J (G13).


Silicon-enhanced coolants are specifically designed for European vehicles, including:

Volkswagen, Porsche, Audi, BMW, Mercedes-Benz, Skoda, Scania.

Features of P-OAT coolant:

Adrad’s Phosphate-based Organic Acid Technology coolant is designed to meet the performance and chemistry required for Japanese and Korean-manufactured vehicles. This coolant comes in pink and blue.


It provides complete anti-freeze and anti-boil protection from -37 °C to 129 °C.


Adrad’s P-OAT coolant provides effective corrosion protection for brass, copper, solder, steel, iron and aluminium through its well-balanced hybrid inhibitor package. This coolant acts to stabilise hard water, protecting non-metal parts and preventing premature water pump failure.


Adrad’s P-OAT coolant is designed to last 250,000 km or 5 years in passenger vehicles.


Adrad’s P-OAT coolant can be coloured pink or blue and meets or exceeds AS 2108-2004 Type A, ASTM D3306, BS 6580:2010, JIS K 2234-2006 Class 2.


Adrad’s P-OAT coolants are specifically designed for Japanese and Korean vehicles including:

Toyota, Subaru, Kia, Mazda, Mitsubishi, Suzuki, Lexus, Nissan, Daihatsu, Honda, Isuzu.

When does coolant need to be changed?

mechanic servicing engine


Maximum service life is only achieved under ideal conditions. Most coolant will need to be changed every few years. Check your car manual for the manufacturer’s recommended service interval.

If you aren’t sure when your car last had a coolant flush and change, a Natrad radiator technician can test your coolant to determine whether it needs to be changed sooner.

radiator specialist

radiator specialist Radiator specialists

We have the parts and know-how to repair or replace your vehicle's radiator.

Can’t I just buy the cheapest coolant?

Industrial chemists have compared the Adrad, coolant sold by Natrad, with cheaper coolants available.

Laboratory testing revealed that cheaper coolants often contain borate buffers. Most manufacturer specifications do not permit the use of this old coolant technology for environmental and toxicity reasons.

The cheaper coolant tested in the lab also contained a higher water content than recommended by international and manufacturer specifications. Additionally, it was found to contain 25% lower concentration of organic inhibitors than the Adrad coolant, which changed the coolant’s freezing point.

This means that corrosion protection offered by cheaper engine coolants will not be as effective as higher quality kinds − particularly for applications like 4WD, commercial vehicles and heavy-duty engines.

Get advice from the professionals

Need more help understanding how to choose the right coolant for your car? Our team of specialists at Natrad are ready to help. We offer valuable radiator advice to keep your engine’s cooling system in the best condition possible. Contact us today.


Book your vehicle in for an inspection and service