Car Coolant 101

May 3rd, 2017 by

Don’t discover you’re in need of coolant the hard way – on the side of the road with an overheated engine. Coolant, also known as antifreeze, is a simple DIY maintenance item, but do you know what kind of antifreeze to use in your car? Gone are the days of grabbing a classic bottle of green, mixing it with water and in the car it goes! With many different types now available in an array of colors, let’s explore the world of antifreeze.


What is antifreeze?

Antifreeze is a liquid that mixes with water and protects your car radiator from overheating or freezing. Most solutions are made from ethylene glycol (EG) or the more environmentally friendly propylene glycol (PG). When mixed with water in your vehicle’s radiator, the coolant alters the freezing and boiling points. Antifreeze also keeps your radiator properly lubricated and fights against corrosion.


Different Types:

Traditional green and yellow antifreeze uses the Inorganic Acid Technology (IAT) chemical basis. IAT formulas contain either EG or PG and have silicate and/or phosphate additives that protect metal radiators and cooling systems from corrosion. IAT coolant has a general recommendation of three years or 36,000 miles for replacement. In the 90s, Organic Acid Technology (OAT) became available. This advanced technology produces a long or extended life coolant. This orange colored coolant is EG or PG based but does not have silicate or phosphate corrosion inhibitors. One reason for this change was that many manufacturers were phasing out copper and brass radiators for lighter weight aluminum radiators. OAT coolant has a replacement recommendation of five years or 150,000 miles. The newest technology is the Hybrid Organic Acid Technology (HOAT). Most new cars use this hybrid coolant that is a combined formula with OAT technology and silicate inhibitors. It is not color coded as its available in a rainbow of colors. It is long lasting like OAT with a five year or 150,000-mile replacement. These are general guidelines only and you should check your vehicles owner’s manual for the recommended coolant replacement interval. Proper maintenance is key to the life of your vehicle.


Distilled or Tap Water?

Antifreeze is available two different ways, concentrated or ready to use. Although ready to use is the more expensive option, it is just that – ready to use. Open the bottle and pour it in. Concentrated coolant needs to be mixed 50/50 with water. There has long been a controversy regarding tap water or distilled water. Tap water generally contains magnesium, calcium, and other minerals. Due to this, it is probably best to be safe than sorry and stick with distilled water. In fact, ready to use formulas are mixed with distilled water at the manufacturing plant.


So Which is Right for Me?

Check your owner’s manual for the manufacturer’s requirements and stick with that. Older cars with copper or brass radiators will most likely require the traditional green (IAT) with the added corrosion protection. Many coolant manufacturers have developed a universal OAT based formula that states it is safe on all makes and models. It is not recommended that you mix different types of coolant. For example, green IAT coolant shouldn’t be mixed with orange OAT coolant.


Dangers of Antifreeze:

Be mindful of the dangers of antifreeze. Antifreeze is toxic and can cause death or permanent damage to the brain and kidneys if ingested. It only takes a small amount to poison kids and pets. Antifreeze has a sweet taste which makes it even more dangerous if left out. Always keep antifreeze out of reach and properly dispose of any leftovers. Lastly, clean up any spills so pets don’t inadvertently lap it up.

Posted in Vehicle Care