Cool runnings - modern engine coolants.

Automotive coolants are a necessity because, just like your lazy cousin Joe, only a small amount of a car’s energy is converted into actual work.

Around one-third of heat produced by the energy in gasoline is converted into work that powers the car. Another third goes out the tailpipe in the form of exhaust, while the remaining third is absorbed by the engine’s coolant. This last bit of heat is dispersed into the air passing by a car’s radiator.

Poor or low quality coolant can freeze, blocking the liquid’s flow and preventing it from doing its job of dispersing your engine’s heat, possibly causing a nasty overheating situation, even if the air temperature is -25° Cesius. Frozen coolant can also expand to crack water pumps and radiators.

Modern coolant is generally mixed with equal parts water and provides freezing protection down to -40° Cesius. Oddly, undiluted coolant will freeze at roughly -15° Cesius as it’s the chemical reactions with water which provide the frigid protection.

Today’s chemistry all but assures coolant a long lifespan. As a bonus, many manufacturers cook up a few additives designed to prevent corrosion forming inside the cooling system. There are three basic types of coolant chemistries available for use in modern automobiles and, no, they are not always immediately identifiable by their colour.

Types of modern coolant.

Until about 20 years ago, choosing a coolant was easy – you bought the green stuff. Now there are three types of coolant:

• Inorganic Acid Technology (IAT)
• Organic Acid Technology (OAT)
• Hybrid Organic Acid Technology (HOAT)

IAT coolant is green in colour and generally called ‘traditional’ coolant. Its main fault are the additives for corrosion prevention tended to break down very quickly, necessitating a flush every couple of years.

OAT coolant showed up in 1996 under GM’s Dex-Cool brand. Other automakers have adopted it or a variant choosing to tint their new coolants amber, pink, blue and green. These coolants form chemical bonds with metal surfaces in a car’s cooling system, forming coatings that are more stable than those of IAT coolants and making the coolant more efficient. They deteriorate slowly and are often called long-life coolants, good for five years or 240,000 km.

HOAT coolant has been used by European manufacturers in recent years. They also fall under the long-life banner. Combining the benefits of IAT and OAT technology, they are very efficient but eye-wateringly expensive to make. While arguably providing the most complete solution of the three, its cost helps to explain its scant adoption rate by the world’s automotive manufacturers.

Don’t mix and match.

Be sure not to combine either of the two modern coolants with the traditional stuff, as the mixture can turn into a soupy sludge. This could clog a car’s cooling system and lead to all kinds of expensive problems.

The main takeaway?

One coolant does not fit all engines. If you think your vehicle does need new coolant, be sure to read the owner’s manual carefully and bring your car to a trusted mechanic for service.

Our Consumer and Technical Services (CATS) team receives questions about car care, buying a new or used vehicle, auto repairs, vehicle inspection, driving costs and more. If you have a question for CATS, call 1-866-464-6448 or email: cats@caasco.ca.