Your Antifreeze/Coolant Questions Answered

It might seem like antifreeze should be used in cold weather and coolant in warm weather, but antifreeze and coolant are two terms synonymous with each other. No matter what coolant your car uses, figuring out the right one for your car and the right amount to keep in the tank in cold and warm weather are critical to your engine's cooling system. Before you add anything to your coolant tank, let’s take some time to answer common questions that people ask about the stuff that keeps your car’s engine running at just the right temperature.

What Kind of Engine Coolant Should I Use?

Antifreeze is really divided into 2 different types – IAT and OAT antifreeze. IAT (inorganic acid technology) antifreeze is the green antifreeze of old, and the universal standard for over 70 years. During the late 80’s, cars began using more and more aluminum parts in engines, and the need to come up with a better, longer lasting antifreeze led to OAT (organic acid technology) antifreeze. While any IAT green antifreeze can be mixed with other green, mixing OAT antifreeze with other types is not recommended. Many manufacturers developed their own blend of OAT antifreeze, with less of more silicates and phosphates, and in doing so, developed a specific color of antifreeze to identify it. You should check your owner’s manual, to check on what type or color of antifreeze your car takes. One of the most common, and longstanding coolants of this type is DEX COOL®, which was developed by GM in the late 1980’s and has been used ever since. You can find out more about the history and details of different types of antifreeze here!

Of course, there are specialty formulas available, and understanding the options there could make your car ownership experience a lot better. Some examples of special variants you might find useful under the right circumstances include:

  • Cold weather protection to -34 degrees is available from many manufacturers
  • Antifreeze that is non-toxic to animals is also very popular
  • Some coolant manufacturers offer extreme heat formulas similar to their cold weather options

In the end, as long as you are choosing a formula that is compatible with your vehicle, what antifreeze to use is largely dependent on your needs.

What Kind of Coolant Does My Car Need?

If you are still unsure what to pick, the best starting point is to buy the coolant recommended in your owner’s manual. If you check the brand’s variants, you can probably find the variants discussed above. If you need a special formula, the manual is also your best bet to learn which one, too. If you don’t know where the manual is and you need to know, AutoZone can help: either ask a store associate or use our coolant lookup to find the right kind for your vehicle’s make and model. Aside from traditional green coolant and many universal coolants, AutoZone also carries Peak’s OEM-specific line of coolant in all the major variants and colors.

Are Basic Antifreeze Formulas the Same?

Prestine and BlueDevil Antifreeze

Almost every antifreeze chosen by OE designers is 95 percent ethylene glycol, but the additives vary a lot from manufacturer to manufacturer and provide each brand and variant with its unique characteristics. The practice of following the recommendations is one of using the antifreeze that tested best under controlled conditions.

How Often Do I Need To Change My Coolant?

A full coolant replacement is generally recommended every three to five years or 100,000 – 150,000 miles by manufacturers, depending on the model, but sometimes these intervals are shorter for older automobiles. OAT antifreeze was formulated to have a much longer life than IAT antifreeze. You can check the specific gravity and color of your coolant to see if it is time. You’ll need a test kit to do it yourself. Most of the time, coolant is good longer than the estimate in the owner’s manual, but sometimes it breaks down early and you lose performance. That’s why regular checks on the coolant will serve you better than an estimate in time or miles. You can get a longer lifespan out of extended life varieties, with some formulas boasting life expectancies as high as five years. If you are curious about extended life varieties, check out whether your manufacturer has made any recommendations about a maximum life formula in addition to the OEM one.

Do I Need To Add Coolant Regularly?

How to flush and fill your coolant

In an ideal world, no. Theoretically your coolant system should be self-contained, reusing the same fluid until it breaks down enough you need to change it. The way things usually work, though is that the system has an overflow tank for a reason, and sometimes it overflows. If the level is slightly too high at a a normal temperature you should be fine. If you’re in extreme heat and temperatures get slightly above optimal, you could also lose coolant you normally depend on due to volume changes.

Checking the coolant on a regular basis will tell you whether you need to add it, as well as how well it is working. Most people will find they only rarely have to add coolant when a vehicle is new, but as cars age many start to have lower efficiency cooling systems. Preventive maintenance and good upkeep in general can both help slow down this process, and a full vehicle restoration can turn back the clock if you are dedicated to preserving a vehicle.

Does Antifreeze Do Anything Else?

Yes! Besides cooling your car’s engine and keeping it from freezing, antifreeze acts as a liquid that resists corrosion, whereas pure water would corrode engine parts and not properly lubricate the moving water pump. That’s why you should always use the mixture recommended in your manual, and why it’s important to keep the coolant at optimal levels.

The Car Is Losing Antifreeze? Is There a Leak?

There are many reasons a vehicle could lose antifreeze, including overflow and evaporation if a cap is loose. If you continue to lose a steady amount of coolant, check carefully around the engine compartment for drips and leaks, and find the front of the water pump to check if the water pump itself is leaking. If you want to find where you’re leaking from, a drop cloth under the vehicle can help pinpoint the leak because it will show a stain where the antifreeze drips. If no leak is found, this is normally a sign of a head gasket leak that could be leaking coolant into either the combustion chamber or into the oil itself. Either way, the system should be properly pressure-tested and checked for leaks, and a head gasket / internal leak.

Consulting a professional for hard to pinpoint leaks can save you time, but coolant system diagnostic guides are out there for the dedicated do-it-yourself enthusiast. Remember to follow all the manufacturer’s recommendations for replacement, including the replacement of hoses and valves at the recommended times. This will help prevent leaks from developing, and it’s much easier than troubleshooting the system for a bad seal or a leaky hose. The best part is, refreshing the system will help it hold on to that efficiency new cars have, so it’s easier to ask your engine to perform at a higher level for longer. If you’d like to take your car in to get the cooling system worked on, consider going to one of our preferred repair shops.

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