A guide to adding antifreeze to your car

Keeping your car topped up with the correct amount of antifreeze is crucial to maintaining your vehicle's health.

What is antifreeze?

Antifreeze is an essential additive in engine coolant that keeps your car’s cooling system from freezing up in cold weather conditions.

Bottles of antifreeze lined up.
Antifreeze can come in all shapes and sizes, but fundamentally it does the same thing.

But it does much more than just stopping your vehicle’s pipes from freezing up: it protects your engine from corrosion, prevents scale build-up and aids in heat transfer to other parts of the engine. 

How does antifreeze work?

Antifreeze keeps your engine running by lowering the freezing temperature of the engine coolant, stopping the water in the system from freezing when temperatures drop. 

Why do we use antifreeze?

We add antifreeze because water as an engine coolant isn’t enough. The crystalline structures created by freezing water can seriously damage your vehicle’s plumbing. 

In addition to dropping the freezing temperature of the engine coolant, it also increases the boiling point; helping stop damage through steam pressure build-ups. It really is a vital component in keeping your car running smoothly. 

You can get hold of two antifreeze types: one ready mixed as engine coolant, or in concentrate form which will need to be topped up with water.

How to mix antifreeze from concentrate

If you’ve bought concentrated antifreeze you will have to dilute it first. Using distilled water (not tap water), mix in the antifreeze concentrate with a ration of 1:1.

In a gallon container, this will be half a gallon of distilled water and half a gallon of antifreeze. Do this and you’re good to go!

Adding antifreeze to your car 

Adding antifreeze mix to your car might seem daunting, but it’s no more difficult than filling up with gas or adding washer fluid, here’s how.

An image of someone pouring antifreeze liquid into a car.
Adding antifreeze to your car is easy.

How to add the antifreeze mix

First of all, make sure:

  • the engine is cool.
  • you roll up loose clothing and keep yourself away from the cooling fans.
  • never to remove the reservoir cap when the engine is running.

Once you’re ready, add your antifreeze to your car engine in five easy steps:

  1. Check how much coolant you have in your system and  that the engine is cool. 
  2. Open up the hood of the car and find the coolant reservoir. This can be translucent or a whitish color.
  3. Loosen the reservoir cap a small amount, let the built up pressure release, then remove the cap completely.
  4. Add the antifreeze mix until it reaches the cold fill line on the vehicle’s reservoir. 
  5. Replace the cap and tighten it until you hear a click, put the hood back down and you’re ready to go.

While you’re at it, we’d recommend using this opportunity to flush your car radiator if it hasn’t been done in a while.

Diagnosing antifreeze problems 

Trouble with antifreeze? We answer some of your pressing antifreeze questions.

What antifreeze do I need?

If you have a car that was made after 1998 it is best to use an antifreeze that uses silicate free, organic acid technology (OAT). 

Cars made before 1998 need antifreeze that uses silicates and isn’t OAT based. 

Why does it smell like antifreeze inside my car?

If the inside of your car is smelling of antifreeze it’s likely your heater core is leaking. It’s important to fix this quickly as it can cause serious damage to your engine, and hit you hard in the wallet.

Add K-Seal to your engine and see if the smell disappears. If not, seek help from a mechanic.

Why is antifreeze coming out of the overflow tank?

If coolant is leaking out of the overflow tank it’s either because of a part failure or an overfilled system. 

If the overflow tank is too full, the coolant antifreeze mix can spill out and make it look like a leak. If this is the case it should only leak a couple of times before correcting itself. If it continues, you may have a leak. Use K-seal to quickly remedy the issue.

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