Just like regular oil changes, adding antifreeze to your engine is a critical part of car maintenance. Let’s go over the types of antifreeze, steps on how to add it to your engine, and answers to some common antifreeze-related questions.
Adding Antifreeze to Your Engine: A Comprehensive Guide

Why Adding Antifreeze is Important
Maintaining the right level of antifreeze (often referred to as coolant) level is essential to your engine’s health and performance. Antifreeze regulates engine temperature, prevents the water in your radiator from freezing or boiling, and inhibits corrosion and scale buildup within the cooling system.
Regularly checking and topping up this fluid can extend your engine’s lifespan and efficiency.
Types of Antifreeze
Ethylene glycol and propylene glycol are the two main types of antifreeze. Ethylene glycol is the most common and is highly effective, while propylene glycol is a more environmentally friendly option. Always check your vehicle’s specifications to determine what type of antifreeze it needs.
Keep in mind: the words “antifreeze” and “coolant” may be used interchangeably, but they’re slightly different products. Antifreeze is coolant before it’s diluted with water. Remember this when you’re browsing, so you know if you need to dilute your fluid.
For more advice on picking the right antifreeze, check out this article.
Antifreeze Tools
Adding antifreeze to your vehicle is a straightforward process, but it requires a few essential tools.
To help everything go smoothly and safely, gather the following before you start your antifreeze change:
Steps to Adding Antifreeze to Your Engine
Once you have everything you need and your engine is cool, follow these steps to add antifreeze to your car’s engine:
- Find the antifreeze/coolant reservoir. This is usually a transparent plastic tank near the radiator.
- Remove the cap and check the fluid level and condition. If the antifreeze is low, it’s time to add more.
- Use a tester to compare the colour of the antifreeze to the recommended colours on the bottle. If it’s the wrong colour, it’s time to fully flush it out and replace it. Use your drain pan to collect the old fluid.
- With your gloves on, prepare your antifreeze mixture according to the product instructions. This is usually a 50/50 mix of antifreeze and distilled water.
- Using the funnel, pour the mixture into the reservoir until it reaches the maximum mark. Do not overfill. Replace the cap securely when done.
- Clean up any spills and check for leaks.
- Properly dispose of any excess or spilled coolant.
Common Antifreeze Questions
Still have questions about antifreeze? Check out some of these common questions to find your answer.
How often should I replace the antifreeze in my car?
For most vehicles, antifreeze should be fully flushed and replaced every two to three years. Your owner’s manual will state exactly when to change your antifreeze.
Top up your antifreeze whenever it drops below the minimum mark on the reservoir. For most vehicles, this will be every four to six months.
Can I mix different brands of antifreeze?
Mixing different brands of antifreeze is not advised unless you’ve confirmed that they’re compatible and meet your vehicle’s specifications. Always consult your manual or a professional before mixing antifreezes.
What if my coolant reservoir is empty?
An empty coolant reservoir could indicate a leak or excessive consumption. Check for visible signs of leaks and refill the reservoir with the appropriate antifreeze mixture. An expert at a NAPA AUTOPRO service centre can help you fix any issues with your coolant reservoir.
More Advice
For other questions about antifreeze, visit your local NAPA Auto Parts store to speak with an expert.
To browse other DIY guides, check out our blog.