Answering the Most Googled Antifreeze/Coolant Questions

What is the Difference Between Antifreeze and Coolant?

“Antifreeze” and “coolant” are sometimes used interchangeably. Technically, “antifreeze” refers to the additive mixed with water to create the solution known as “coolant.”

Why are Coolants Color-Coded?

In the past, coolants were dyed according to their chemical composition. Green indicated an ethylene glycol-based coolant, which is the most common type of coolant used in vehicles and is toxic. Pink was indicative of a propylene glycol-based coolant, which is non-toxic. These were used in potable water systems like campers or RVs.

We no longer rely on color-coded coolant for vehicle compatibility purposes. Most coolants are universally compatible. Now, the colors are primarily representative of brand ownership. Even with this in mind, it’s recommended that you follow the manufacturer’s recommendations regarding coolant type and mixing ratios for your specific vehicle.

What Kind of Coolant Should I Use?

BG Universal Coolant/Antifreeze

For most passenger vehicles, any universal coolant should do the trick. Most coolants on the market are Organic Acid Technology (OAT) Inhibitors. OAT coolants use organic acids instead of inorganic additives like silicates and phosphates, which provide protection from rust. Since OAT coolants inhibit corrosion so well, they tend to have a much longer shelf life.

Because most coolants are OAT coolants, that means they are universally compatible with each other. So, despite the color or the recommendations, if a coolant says “universal,” it can be mixed or topped off with other universal coolants.


How Often Do I Need to Change My Coolant?

BG recommends getting a Cooling System Service:

  • If coolant is contaminated, low, or more than five years old
  • At 30,000-mile intervals
  • Engine temperature is running high
  • Coolant tests positive for acidity
  • Alongside cooling system repairs, such as the radiator, water pump, or thermostat

When is Coolant Too Acidic?

Coolant is measured on the pH scale, where a lower pH indicates a higher acidity. For coolant, 7.5 to 10 is the acceptable range. Anything below 7.5 is considered too acidic for coolant. This is when the metal parts of the cooling system start to erode.

Transversely, suppose the pH balance is above 10. In that case, that means it’s too basic, which could potentially break down the additives in your coolant.

Why Does Coolant Need to Be Flushed?

coolant flush

Although coolant lasts much longer now than its predecessors because of corrosion inhibitors, these additives and the coolant itself, unfortunately, deteriorate over time.

So, while you can go much longer between getting your coolant flushed completely, it must still be monitored. Once it has reached a certain point, though, the coolant is too dirty and contaminated and needs to be fully replaced.

Why Does Coolant Turn Brown?

Your coolant might be brown because of a head gasket issue. Hydraulic fluid could have entered your cooling system. If it’s not that, then it’s contaminants in the coolant due to rust buildup. The additives in your coolant have broken down.

Why Does Coolant Smell Sweet?

The sweet smell associated with coolant is due to the ethylene glycol, the main ingredient in most coolants. Ethylene glycol smells and tastes sweet because it has hydroxyl groups in its molecular structure; sugar has a similar structure.

Coolant smelling sweet should serve as a warning sign for potential coolant leaks, but it also poses a risk. Ethylene glycol is highly toxic if ingested. The sweet taste attracts animals and maybe even children. Keep it out of kids’ reach so they aren’t tempted to drink what they might think is juice or soda. If you see a leak puddling in your garage or driveway, clean it immediately so pets can’t lap it up.

Regular Vs. Prediluted Antifreeze?

Regular vs. Prediluted Coolant/Antifreeze

Regular antifreeze comes 100% undiluted by water. But most people doing at-home coolant changes are probably using prediluted antifreeze for the sake of convenience.

Most prediluted coolant comes with a mix of 50% antifreeze and 50% water. This mix works in almost every climate except for anything under 32 degrees Fahrenheit. The recommended mix for a higher risk of freezing is 60% antifreeze and 40% water.

The con of buying prediluted is the expense. For a cheaper option, buying regular, undiluted antifreeze and mixing it with distilled water to the correct proportions is cost-effective. For those who prefer ease over cost, prediluted is the best option.

How Does Antifreeze Not Freeze?

Ethylene glycol has a lower freezing point than water. Adding more antifreeze in your antifreeze/water ratio will lower the freezing point, so a 60:40 ratio is recommended for freezing temperatures. Antifreeze also raises water’s boiling point, which helps prevent engine overheating.

How Does Antifreeze Get into Engine Oil?

If there is coolant in your engine oil, your engine could be in big trouble. The most common cause is a faulty head gasket, as mentioned above. The head gasket is the joint between the engine block and cylinder head. If there’s a leak, coolant can mix into the engine oil.

Suppose coolant does make it to your engine. In that case, it can lead to engine seizure, especially if the oil properties aren’t working correctly. Engine seizure happens when moving parts become stuck due to a crazy amount of friction and heat. Get a thorough inspection by a qualified mechanic to identify the source and prevent further damage.

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