Unless you are driving a vintage VW or Porsche, your engine depends on coolant to keep operating temperatures in check. Typically the terms “coolant” and “antifreeze” are used interchangeably. While they do the same job in an engine, there are some differences you can read about here. Picking the right coolant for your vehicle isn’t hard, but you do need to understand a few things so you can make the right decision.
What Does Coolant Do?
Coolant does exactly what the name implies, it cools the engine. It takes heat from areas inside the engine, and moves that heat (via the liquid coolant) to the radiator where the heat can be dissipated. It also carries engine heat to the climate control system heater core where that same engine heat can be distributed inside the passenger cabin. Coolant also lubricates the water pump and carries the important additives that keep corrosion from forming inside the engine.
There are three main types of coolant: Inorganic Acid Technology (IAT), Organic Acid Technology (OAT), and Hybrid (HOAT). IAT is good old fashioned green (sometimes yellow) coolant everyone thinks of when saying the word “antifreeze.” IAT tends to become acidic over time and corrodes the cooling system, so it was phased out. Next up was OAT which lasts longer than IAT but still had some flaws in the corrosion resistance department. Clever scientists came up with HOAT which has good corrosion resistance while also lasting a long time. While some may consider straight water a coolant, it is terrible at standing up to extreme temperatures plus it will corrode the cooling system from the inside. Never use just water in a cooling system.
Picking The Right Coolant
The engineers who designed your engine spent a lot of time making sure everything would work together in harmony, and that includes the coolant that gets poured in the radiator. The first stop for picking the right coolant should always be your vehicle owner’s manual. Inside the owner’s manual you will find two pieces of important information, usually listed in the specifications section. The first will be the cooling system capacity (either in quarts or liters) so you know how much to buy if you do a coolant flush. The second piece of vital information is the coolant name and specification. Almost every automobile manufacturer uses their own brand of coolant, but almost every one has a third-party equivalent available. The coolant specification (usually some cryptic string of letters and numbers) is the key to determining if a coolant is compatible with the vehicle. If a coolant states that it meets the same specifications as the original manufacturer coolant, then you can use it.
In recent years chemists created “universal” coolants that can be used in a multitude of vehicles with different specifications. In the past mixing coolant could spell trouble depending on how each type would react to the other. These coolants are designed to not react with the existing coolant in the engine. While universal coolant is a welcome product, you should still compare the specifications to make sure it is designed to work in your engine.
Check out all the engine coolant products available on NAPAOnline, or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to pick the right coolant, chat with a knowledgeable expert at your local NAPA Auto Parts store.
With an automotive writing career spanning over two decades, Brian has a passion for sharing the automotive lifestyle. An avid DIYer he can usually be found working on one of his many project cars. His current collection includes a 1969 Olds Delta 88 convertible and a slant-6 powered 1975 Plymouth Duster.