Choosing the Right Antifreeze/Coolant for Your Car

Learn how to find the correct type of antifreeze or coolant for your vehicle.

With so many different types of engine coolant and antifreeze available to choose from, it can be difficult to determine which one is right for your vehicle. If you’re not sure where to start, follow this guide from Blain’s Farm & Fleet to help pick the best one for your car.

Does the color matter?

Antifreeze color does not matter, but the chemicals that make up the antifreeze do. Relying on the color of the coolant is not a reliable way to tell what’s in an antifreeze.

You should consult the maintenance chart in your vehicle’s owner’s manual to find which antifreeze the manufacturer recommends. Different car makers have their own antifreeze formulas. They’re designed to work best with the metals the engine and cooling systems are made of.

There are three main types of antifreezes to choose from:

• Inorganic Additive Technology (IAT): This type of coolant is green and is typically used in older cars. You should change it about every two years or 24,000 miles.
• Organic Acid Technology (OAT): OAT coolant is usually orange and is most commonly used by General Motors cars. You should change it about every five years or 50,000 miles.
• Hybrid Organic Acid Technology (HOAT): HOAT coolant comes in a variety of colors and is used in a range of different cars. You should change it about every five years or 50,000 miles, although some types can last even longer than that.

Following the manufacturer’s recommendations will ensure that you are getting the one that works best for your vehicle.

Will using the wrong antifreeze damage your vehicle?

Probably not, but not maintaining the right coolant-to-water ratio could. You should always keep the coolant mixture in cars around 50% distilled water and 50% antifreeze. Having too much antifreeze in the mixture causes unnecessary wear on your water pump.

Antifreeze is thicker than water. And your water pump has to work harder to pump a thicker coolant mixture through your vehicle’s cooling system. Having too much water can prevent the antifreeze from fighting corrosion and buildup in the cooling and engine system.

Using non-distilled water to dilute your coolant can also harm your vehicle. Since all tap water and well water contains various minerals that react with metal, using it can cause mineral buildup in your cooling system, clog your water pump, and damage your heater core. This may cause the heater in your car to fail.

Many antifreeze makers offer a pre-mixed 50-50 coolant. This is always 50% antifreeze and 50% distilled water.

Can I mix different antifreezes?

Most experts say that you should not mix propylene glycol (PG) antifreezes with ethylene glycol (EG) ones. The two can react with each other and create deposits and residue in your cooling system. You can avoid this by following your vehicle’s manufacturer recommendations.

Mixing any brand or color of PG antifreeze with another brand or color of PG will not cause any problems in your vehicle, as long as you keep your coolant mixture around 50-50. The same goes for different brands and colors of EG antifreeze.

You can mix a PG with a PG, or an EG with and EG, but not a PG with and EG. If you own a General Motors vehicle that uses Dex-Cool antifreeze, use only antifreezes that meet the Dex-Cool specifications.

If you suspect that you may have EG and PG coolant mixed in your vehicle, have your radiator flushed and filled as soon as possible. You should have your radiator flushed every 35,000 miles as part of your regular maintenance schedule.

For more vehicle guides and how-tos, check out our Maintenance & Repair Blog.