In short: Use Honda Genuine Long-Life Coolant Type 2 (Honda Type 2), typically sold in a pre-mixed 50/50 formulation with distilled water.
This article explains which coolant to use for a 2018 Honda Civic, how to identify the right Type 2 specification, and how to service or replace the coolant safely to keep the cooling system operating effectively.
Official specification and recommended products
Honda specifies using Honda Genuine Long-Life Coolant Type 2, or any coolant that explicitly meets Honda’s Type 2 specification. The coolant is designed for the Civic’s aluminum engine and cooling system, and it is commonly available as either a pre-mixed 50/50 solution or a concentrate that you dilute with distilled water to achieve the same ratio. Stick with Type 2 only and avoid mixing different coolant types.
- Honda Genuine Long-Life Coolant Type 2 (pre-mixed 50/50)
- Coolants that are clearly labeled as meeting Honda Type 2 specification (verify compatibility with aluminum engines and 50/50 mix instructions)
- Distilled water for diluting concentrate to a 50/50 mix, if you purchase concentrate rather than pre-mixed coolant
Using anything outside the Type 2 specification or mixing incompatible coolants can lead to corrosion, deposits, or improper cooling performance.
How to service or replace the coolant
When changing or topping off coolant, follow these steps to ensure a proper fill and to help remove air from the system. Always work with a cool engine and use appropriate safety precautions.
- Park on a level surface and allow the engine to cool completely. Place a drain pan beneath the radiator drain or reservoir, depending on your vehicle’s drain method.
- Open the radiator drain plug (if your Civic has one) or remove the reservoir cap to allow coolant to drain out.
- Optionally flush the cooling system according to your service preferences and the manufacturer’s guidance.
- Close the drain, then refill with a 50/50 mix of Honda Type 2 coolant and distilled water, or install pre-mixed 50/50 coolant.
- Start the engine and set the heater to hot. Run the engine until the thermostat opens and air is purged from the system, adding coolant as needed to maintain the correct level.
- Check for leaks and verify the coolant level after the engine has cooled back down.
Bleeding air and maintaining the correct coolant level are essential for preventing overheating and ensuring consistent performance.
Why choosing the right coolant matters
Using the correct Type 2 coolant protects the Civic’s aluminum components, maintains proper freeze/boil-point performance, and supports the cooling system’s longevity. Honda’s Type 2 formulation is engineered to meet the specific needs of the Civic’s engine and cooling system architecture.
Summary
For a 2018 Honda Civic, the recommended coolant is Honda Genuine Long-Life Coolant Type 2, available either as pre-mixed 50/50 or as concentrate to be diluted with distilled water. Use only Type 2 coolant and avoid mixing with other formulations. When servicing, drain as needed, flush if desired, fill to the correct level with the appropriate 50/50 mix, and bleed the system to remove air. Regular checks help prevent overheating and extend engine life.
What color is Honda Civic coolant?
Honda Coolant Color
You'll find that most Organic Acid Technology (OAT) coolants can be found in orange, yellow, red, or purple, while Hybrid Organic Acid Technology (HOAT) coolants are orange and yellow. However, you also have Inorganic Acid Technology (IAT) coolants that are usually green, or sometimes blue.
What type of coolant does a Honda Civic need?
/Coolant Type 2
Always use Honda All Season Antifreeze/Coolant Type 2. This coolant is pre-mixed with 50 percent antifreeze and 50 percent water. Never add straight antifreeze or plain water.
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What type of coolant for 2018 Honda Civic?
Type 2 Antifreeze
Type 2 Antifreeze/Coolant.
Do all Hondas use type 2 coolant?
What Type of Coolant Does Honda Vehicles Use? Whether you drive a pre-owned Honda Accord or brand-new Pilot, each release year and model has a brand-recommended coolant, with the most common one known as the Long Life Antifreeze Coolant Type 2.