2018 Honda Odyssey Coolant Capacity & Type

Quick Answer

The 2018 Honda Odyssey typically holds between 7.0 and 7.5 quarts (6.6 to 7.1 liters) of coolant in its cooling system.

• Total Cooling System Capacity: 7.0 - 7.5 quarts (6.6 - 7.1 liters)
• OEM Coolant Spec: Honda Long-Life Antifreeze/Coolant Type 2 (Blue, P-OAT Hybrid Coolant)
• Mix Ratio: 50/50 Prediluted (Do NOT add water)

Capacity by Engine Option

All 2018 Honda Odyssey models are equipped with the same 3.5L V6 engine, so the coolant capacity remains consistent across all trims.

Flush Interval

Honda recommends specific maintenance intervals for the cooling system to ensure optimal performance and longevity.

• Normal Duty: The initial coolant change is recommended at 120,000 miles or 10 years, whichever comes first. After that, it's typically every 60,000 miles or 5 years.
• Severe Duty: If your driving habits fall under severe conditions (e.g., frequent towing, driving in extreme temperatures, heavy city traffic), it's advisable to inspect your coolant more frequently and consider changing it closer to the 60,000-mile or 5-year mark for the initial change, and then every 30,000 miles or 2-3 years.

Always refer to your vehicle's owner's manual for the most accurate and up-to-date maintenance schedule.

How to Refill & Bleed

Properly refilling and bleeding the cooling system is crucial to prevent air pockets, which can lead to overheating. Honda Odyssey vehicles typically don't have a dedicated bleed screw, relying on a thorough burping process.

1. Safety First: Ensure the engine is completely cool before starting. Loosen the radiator cap slowly to release any pressure.
2. Drain Old Coolant: Open the radiator drain plug (usually located at the bottom of the radiator) and allow the old coolant to drain into a suitable container. You might also need to drain from the engine block if accessible.
3. Flush (Optional but Recommended): If performing a full flush, close the drain plug, fill with distilled water, run the engine with the heater on until warm, then drain. Repeat until the water runs clear.
4. Refill: Close all drain plugs. Slowly fill the radiator with the Honda Long-Life Antifreeze/Coolant Type 2 (prediluted 50/50). Fill the reserve tank to the MAX line.
5. Burp the System: Leave the radiator cap off. Start the engine and let it run until it reaches operating temperature (the cooling fans should cycle on). As the engine warms, air bubbles will escape. Squeeze the upper and lower radiator hoses repeatedly to help release trapped air.
6. Maintain Level: As the air escapes, the coolant level in the radiator will drop. Continuously top off with coolant until no more bubbles appear and the level stabilizes.
7. Final Check: Once the engine is cool, recheck the coolant level in both the radiator and the reserve tank and top off as needed. Check for leaks.

• Note: Some technicians may recommend using a vacuum-fill tool for a more thorough air removal, especially if you're experiencing persistent air pockets.

Common Cooling System Issues for this Generation (2018 Honda Odyssey)

While the 2018 Honda Odyssey is generally reliable, some cooling system issues can arise:

• Coolant Leaks: Leaks can occur from various components such as hoses, the radiator, water pump, or thermostat housing. Regularly check for puddles under the vehicle or a sweet, syrupy smell.
• Water Pump Failure: The water pump circulates coolant. A failing water pump can lead to overheating. Symptoms include a whining noise, coolant leaks from the pump, or an overheating engine.
• Thermostat Issues: A faulty thermostat can get stuck open or closed. If stuck closed, the engine will overheat. If stuck open, the engine may take a long time to reach operating temperature or run cooler than optimal.
• Radiator Fan Problems: The cooling fans are essential for dissipating heat, especially in stop-and-go traffic or at low speeds. Issues can include a faulty fan motor, relay, or fuse, leading to overheating.
• Degradation of Coolant: Over time, coolant loses its protective properties, leading to corrosion and decreased heat transfer efficiency. Adhering to flush intervals with the correct coolant type is vital.

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