2018 Honda Civic Fluid Specs

Quick Reference

Fluid	Type/Spec	Capacity
Engine Oil	0W-20, API SN/ILSAC GF-5	3.4–4.4 US qt (verify)
Engine Coolant	Honda Long Life Blue, Type 2	~1.5 gal (verify)
CVT Fluid	Honda HCF-2	3.7–4.2 US qt (verify)
Manual Trans Fluid	Honda MTF	1.8–2.4 US qt (verify)
Brake Fluid	Honda Heavy Duty DOT 3	As needed
Windshield Washer	OEM or quality aftermarket	~1 gal

Engine Oil

Specification: API Certified SN / ILSAC GF-5, SAE 0W-20

Capacity: 3.4 US qt (1.5L R16) to 4.4 US qt (2.0L K20/1.5L L15B7 Turbo). Always verify capacity with the dipstick.

Honda specifies a high-quality 0W-20 synthetic or synthetic blend oil displaying the American Petroleum Institute (API) certification starburst. For the 2018 model year, this corresponds to the API SN and ILSAC GF-5 categories. Using a 0W-20 viscosity is critical for the proper function of the VTC (Variable Timing Control) system and for ensuring optimal fuel economy and cold-start protection.

While newer specifications like API SP and ILSAC GF-6A have since been released and are backward-compatible, the original recommendation is API SN. For the 1.5L turbocharged engines, using a high-quality synthetic is especially important to prevent intake valve deposits and combat Low-Speed Pre-Ignition (LSPI). Change intervals are determined by the Honda Maintenance Minder system, which typically recommends a change every 7,500 to 10,000 miles under normal conditions.

Engine Coolant

Specification: Honda Long Life Antifreeze/Coolant Type 2 (Blue)

Capacity: Approximately 1.5 gallons for a full drain and fill, but verify with OEM service information.

Honda vehicles require a specific P-HOAT (Phosphate-enhanced Hybrid Organic Acid Technology) coolant, sold as Honda Long Life Blue Coolant Type 2. It comes pre-mixed 50/50 with deionized water and should never be diluted further.

A common and costly mistake is using a "universal" or incorrect type of coolant. Mixing coolant chemistries can cause gelling, which can clog the radiator, heater core, and small coolant passages within the engine, leading to overheating and expensive repairs. Never add green, orange, or yellow coolants to the system. If the factory blue coolant is unavailable, use only a coolant specifically labeled as a compatible P-HOAT for Asian vehicles as a temporary top-off.

The factory coolant is designed to last up to 10 years or 100,000 miles for the initial fill, with subsequent changes recommended every 5 years or 50,000 miles.

Transmission Fluid

Transmission fluid type depends entirely on which transmission the vehicle is equipped with.

Continuously Variable Transmission (CVT)

Specification: Honda HCF-2 Continuously Variable Transmission Fluid

Capacity: 3.7–4.2 US qt for a drain and fill.

Civics equipped with the CVT automatic absolutely must use Honda Genuine HCF-2 fluid. This is not the same as the older CVT fluid (HMMF) used in previous generations. Using any other fluid, including "universal" CVT fluids or other Honda ATF, will cause driveability issues like shuddering, slipping, and eventual catastrophic failure of the transmission. There is no compatible aftermarket equivalent. Intervals are dictated by the Maintenance Minder, typically every 25,000 to 30,000 miles.

Manual Transmission

Specification: Honda Manual Transmission Fluid (MTF)

Capacity: 1.8–2.4 US qt (verify for your specific model).

For the 6-speed manual gearbox, Honda MTF is the required fluid. This fluid has a unique viscosity and friction modifier package designed for the carbon-lined synchronizers in Honda transmissions. Using standard gear oil or another brand's MTF can result in notchy shifting, grinding, and premature wear. It provides excellent shift feel in a wide range of temperatures. The Maintenance Minder will advise on change intervals, often around 60,000 miles.

Brake Fluid

Specification: Honda Heavy Duty Brake Fluid DOT 3

Capacity: The system should be bled until clean fluid appears at all four calipers, typically using 1-2 quarts.

The factory fill is a high-quality DOT 3 brake fluid. While DOT 4 and DOT 5.1 fluids have higher boiling points and are technically compatible (as they are all poly-glycol based), it is best practice to stick with the OEM recommendation unless you are upgrading the brake system for high-performance use. Never, under any circumstances, use DOT 5 fluid, which is silicone-based and will damage the entire brake system. Brake fluid is hygroscopic, meaning it absorbs moisture from the air, which lowers its boiling point and can cause corrosion. For this reason, it should be replaced every 3 years, regardless of mileage.

Power Steering Fluid

The 2018 Honda Civic is equipped with an Electric Power Steering (EPS) system. It does not use any hydraulic fluid. No service or fluid checks are required.

Windshield Washer Fluid

Specification: Any quality, brand-name windshield washer solvent.

There is no specific OEM "spec" for washer fluid. Use any good quality blue or de-icing (winter) washer fluid. It is wise to avoid using plain water, as it does not clean effectively and can freeze in the winter, potentially cracking the reservoir or damaging the pump.

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