2020 Honda Civic Coolant Capacity and Type

The 2020 Honda Civic's cooling system capacity varies by engine, ranging from 4.0 to 6.2 quarts (3.8 to 5.9 liters) for an initial refill.

Quick Answer

• Total Cooling System Capacity: 4.0 to 6.2 quarts (3.8 to 5.9 liters), depending on engine and transmission.
• OEM Coolant Specification: Honda Long Life Antifreeze/Coolant Type 2 (Blue, Silicate-free and borate-free HOAT).
• Mix Ratio: 50/50 with distilled water. Sold pre-mixed.

Capacity by Engine Option

Flush Interval

The original factory-fill coolant in a 2020 Honda Civic is designed to last for a significant period. Subsequent changes are on a shorter schedule.

• Normal Duty: The first coolant change is recommended at 10 years or 120,000 miles. After the initial change, replace the coolant every 5 years or 60,000 miles.
• Severe Duty: If the vehicle is driven in extreme temperatures, mountainous terrain, or used for towing, it is wise to shorten this interval. Consider a 60,000-mile initial flush and subsequent changes every 30,000-40,000 miles.

How to Refill & Bleed

Refilling and bleeding the air from a modern Civic’s cooling system is critical to prevent overheating. While a vacuum-fill tool is the professional standard, you can do it manually.

1. Safety First: Ensure the engine is completely cool.
2. Lift the Vehicle: Safely raise and support the front of the vehicle to help air travel to the radiator cap, which should be the highest point.
3. Refill Slowly: Using a spill-proof funnel that seals onto the radiator neck, slowly pour in the Honda Type 2 coolant. This allows air bubbles to escape as you fill.
4. Bleed the System: Start the engine with the heater on its highest temperature setting and the fan on low. Let the engine idle. You will see bubbles coming up into the funnel as the thermostat opens and air purges from the system.
5. Monitor Temperature: Keep an eye on the temperature gauge. Let the engine run until the radiator fan cycles on and off at least twice. Add coolant to the funnel as the level drops.
6. Finalize: Shut off the engine and let it cool completely. Top off the radiator and fill the coolant reservoir to the "MAX" line.

There are no specific bleed screws on most Civic models; the system is designed to be self-bleeding when this procedure is followed correctly.

Common Cooling System Issues

The 10th generation Civic (2016-2021) is generally reliable, but some cooling system issues have been noted, particularly with the 1.5L turbo engine.

• Leaking Water Pump: Some owners have reported premature water pump failures, leading to coolant leaks and potential overheating. Symptoms include a whining noise from the engine bay, visible blue coolant drips under the vehicle, and a low coolant level.
• Thermostat Issues: Though less common, a thermostat stuck open or closed can cause issues. A stuck-open thermostat will lead to slow engine warm-up and poor heater performance, while a stuck-closed thermostat will cause rapid overheating.
• Head Gasket Seepage: On a small number of early 10th-gen models, minor head gasket leaks were reported, sometimes allowing coolant to seep externally or, more seriously, into the combustion chamber. This is not widespread on the 2020 model but is worth being aware of if you notice persistent, unexplained coolant loss.

Properly maintaining your Civic’s cooling system with the correct Honda Type 2 fluid and proper bleeding procedures is the best way to ensure a long, trouble-free service life. Find a trusted shop on Repairius.