The 2018 Hyundai Tucson should use Hyundai Genuine Long Life Coolant (HOAT), an ethylene glycol–based, silicate-free and phosphate-free coolant, typically sold premixed 50/50 with distilled water. If OEM coolant isn’t available, choose a high-quality HOAT coolant that explicitly states compatibility with Hyundai/Kia vehicles and follow the 50/50 mix guideline.
Hyundai’s cooling system is designed for modern, aluminum-intensive engines that rely on a durable, long-life coolant. Using the correct specification helps prevent corrosion, scale buildup and overheating, while ensuring the warranty and maintenance schedule remain intact. Always consult your owner’s manual or a dealer if you’re unsure about a substitute or if your vehicle is in a market with slightly different coolant formulations.
Recommended coolant specifications
Before listing the key criteria to look for when buying coolant, note that Hyundai’s guidance centers on a HOAT (Hybrid Organic Acid Technology) formulation that is silicate- and phosphate-free and ethylene glycol–based. The coolant is commonly sold as a premixed 50/50 solution, but concentrated formulas can be mixed to the same ratio if you choose to dilute yourself.
- Type and chemistry: HOAT coolant that is ethylene glycol–based and explicitly labeled as silicate-free and phosphate-free. Prefer Hyundai Genuine Long Life Coolant or an equivalent high-quality HOAT that confirms compatibility with Hyundai vehicles.
- Concentration: Premixed 50/50 with distilled water is typical. If using concentrated coolant, mix it with distilled water to achieve a 50/50 ratio before adding it to the cooling system.
- Compatibility: Suitable for aluminum engine components, radiator plastics, and seals used in modern Hyundai engines. Avoid silicate-containing or inorganic acid technology that isn’t approved for Hyundai/Kia systems.
- Certifications and guidance: Look for product labels that reference Hyundai/Kia compatibility or general automotive HOAT standards, and verify it meets local automotive cooling system specifications (e.g., ASTM or OEM guidelines).
- Color is not a reliable indicator: Coolant color varies by market and manufacturer, so do not rely on color alone to identify the correct product.
In practice, the simplest route is to use Hyundai Genuine Long Life Coolant or a reputable HOAT coolant that clearly states it is suitable for Hyundai or Kia vehicles. If you’re unsure about a substitute, ask a dealer or service professional for confirmation.
How to replace or top off coolant
Before performing any coolant work, ensure the engine is cool and the vehicle is on a level surface. The steps below cover topping off with premixed coolant and a full drain-and-refill procedure. If you’re not confident, have a professional handle the job.
- Park on a level surface, engage the parking brake, and allow the engine to cool completely before opening the radiator cap or reservoir cap.
- Locate the coolant reservoir and check the level on the cold mark. If topping off, use premixed coolant and add slowly until reaching the MAX or full line.
- If performing a full drain and refill, locate the radiator drain plug (or the reservoir, if no drain) and carefully drain the old coolant into a suitable container. Dispose of used coolant per local regulations.
- Flush the cooling system with distilled water if you’re performing a complete replacement, then refill with a 50/50 premixed Hyundai-approved coolant.
- Reinstall the cap securely, start the engine, and run it to operating temperature with the heater on to bleed any trapped air. Check for leaks and re-check the level once the engine has cooled again, adjusting if necessary.
- Properly dispose of or recycle used coolant and rinse any tools or spill areas.
Additionally, consult your owner’s manual for any model-specific steps or bleed procedure. If you notice unusual symptoms—overheating, sweet-smelling exhaust, or coolant leaks—address them promptly with professional service.
Key terms to know
HOAT: Hybrid Organic Acid Technology coolant, designed to provide long-lasting protection with a balance of organic acids and inorganic inhibitors; typically silicate-free and phosphate-free in modern formulations. Premixed vs. concentrate: Premixed reduces the risk of improper dilution; concentrate requires accurate mixing with distilled water to achieve the correct 50/50 ratio. OEM compatibility: OEM-approved coolants ensure compatibility with specific engine materials and sealing systems.
Common questions about Hyundai Tucson coolant
Can I mix different brands? It’s best to avoid mixing brands unless both are explicitly labeled as Hyundai/Kia compatible HOAT coolants. Incompatible formulations can cause corrosion or deposits. If you must mix, do so in a controlled manner with the engine cool and consult a service professional.
Is color a reliable indicator? No. Coolant colors vary by manufacturer and market. Always verify the specification and compatibility rather than relying on color alone.
How often should I replace the coolant? Hyundais typically use long-life coolant, but replacement intervals vary by market and coolant type. Always follow your owner’s manual or a Hyundai service advisor for the recommended interval; some regions specify around 5 years/60,000 miles or longer with OEM formulations.
Bottom line: For a 2018 Hyundai Tucson, use Hyundai Genuine Long Life Coolant (HOAT) or an equivalent HOAT that explicitly states Hyundai/Kia compatibility, and follow the 50/50 premix guideline or the manufacturer’s mixing instructions. Regular checks and proper disposal of old coolant help keep the cooling system in good shape and preserve engine integrity.
Summary: The correct coolant for a 2018 Hyundai Tucson is an ethylene glycol–based HOAT coolant that is silicate-free and phosphate-free, ideally Hyundai Genuine Long Life Coolant or an OEM-approved equivalent, typically premixed 50/50. Always refer to the owner’s manual for the exact specification and interval, and consult a professional if you’re unsure about substitution or coolant maintenance.