Car Oils And Fluids

Antifreeze Vs. Coolant: What You Need To Know To Keep Your Engine Running Well

Mike Cross
Updated Aug 10, 2022
Antifreeze vs Coolant

Antifreeze and coolant are vital fluids to keep your vehicle running at optimal performance. Though these are often overlooked, they are just as important as oil to check and maintain regularly. 

In this article, we'll cover:

  • What are antifreeze and coolant?
  • What do they do?
  • How often should you check and change antifreeze and coolant?
  • How do you top off your antifreeze and coolant?
  • How do you tell what kind of coolant you need for your vehicle?

Antifreeze Vs. Coolant

Antifreeze and engine coolant do the same job in your vehicle. The primary ingredient in both is ethylene glycol. The engine coolant system pumps these fluids around the engine block to maintain a constant operating temperature. The main difference between the two is dilution. 

Antifreeze, as the name suggests, keeps the water in the engine coolant system from freezing during extremely low outdoor temperatures. If water freezes in the pump or any other part of the system, it can damage your engine

Coolant raises the boiling point of the water in the system so that it doesn't boil off and evaporate away. 

The main distinction between antifreeze vs. coolant is the need to mix antifreeze with water before adding it to the coolant reservoir. Usually, you need to mix half water and half antifreeze. A jug labeled coolant is premixed and doesn't need diluting. Always read the label to know exactly what to do. 

Why Do You Need Antifreeze or Coolant?

As outdoor temperatures fluctuate with the seasons, your engine needs some protection against extreme rises and falls on the thermometer. 

Antifreeze keeps the water flowing around your engine block from freezing in winter so that it runs smoothly. In summer, when overheating is more likely, the coolant keeps the water from boiling off and maintains a consistent temperature in the engine. 

Checking Your Antifreeze or Coolant Level

Antifreeze vs Coolant
Antifreeze vs Coolant

You should check your antifreeze/engine coolant level before summer and winter. Since these fluids help your engine maintain the right operating temperature during extreme fluctuations, you want to make sure they are at optimum levels before the hottest and coldest seasons. 

Also, check your coolant whenever the light on your dashboard comes on. 

Most times, you can just top off your antifreeze or coolant. You should drain and change it completely about every 30,000 to 50,000 miles depending on the type of fluid your vehicle needs. 

How To Check the Coolant Level

Why And What To Do When Oil In The Coolant Reservoir

First, locate the coolant reservoir. It will be a transparent tank under the hood near the front. Never open the lid when the engine is hot! It can spray hot liquid because the water pump system is pressurized.

The tank has two indicator lines, one near the top and one near the bottom. You need to add more fluid if it is below the bottom line. Read the directions on the jug to see if you have to mix it with water. 

How To Change Your Engine Coolant

  • For safety reasons, allow the engine and radiator to cool completely.
  • Turn on the heat control to maximum heat. This action opens up the radiator core allowing all the coolant to drain out.
  • Remove the radiator cap, place a catch pan under the radiator underneath the car, and loosen the drain plug.
  • Allow all the coolant to drain.
  • Move the catch pan under the engine and remove the engine drain bolt. This step allows any fluid in the engine block or heater core to drain out. 
  • Use some high-temp thread sealant on the engine drain bolt and replace the washer. Check your owner's manual for the right tightening pressure.
  • Replace the radiator drain plug.
  • Remove the coolant reservoir, drain it, and place it back in the correct position. 
  • Refill the reservoir with new antifreeze without exceeding the max fill line. 

Types of Antifreeze and Coolant

When shopping for a new antifreeze/coolant, you'll see a range of colors. The color does not indicate how the fluid works or what vehicles it is for. 

There are three types of antifreeze. 

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

Older model vehicles usually use IAT coolant. It needs to be changed about every 24,000 miles making it much less efficient than more recent technology. OAT and HOAT formulas need changing after 50,000 miles unless otherwise specified on the bottle. 

Some dealerships sell coolant for specific models. You can buy it there, but you'll likely pay more than at your local auto parts store. Aftermarket options for coolant generally say what kinds of cars they work in. 

Read the label on the coolant and check your owner's manual to make sure you are using the proper coolant. Write yourself a note in your manual about which brand you purchased so you can stay consistent next time you do maintenance.

Coolant Colors

The color of the coolant doesn't tell you exactly what kind of coolant you have. But there are some commonalities. IAT coolant is green. If you have an older model, you're probably familiar with green antifreeze. Usually, OAT coolants are orange, red, yellow, or purple. HOAT coolants are mostly orange or yellow. 

Summing Up

What is the difference between antifreeze vs. coolant? They are basically the same thing and do the same job for your engine. The main difference between the two is whether you have to mix it with water before adding it to the coolant reservoir under your hood. 

Antifreeze/coolant keeps your engine running at a consistent temperature. It ensures that the water doesn't freeze in the winter or boil off in the summer. 

Maintaining your coolant level is a fairly straightforward task that you can do without a mechanic or dealership. Staying up to date with your engine's coolant saves you from expensive potential damage. 

Mike Cross
Life is too short to drive with stock audio

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