2020 Toyota Highlander Coolant Capacity & Type Guide

The 2020 Toyota Highlander holds approximately 9.0-9.5 quarts (8.5-9.0 Liters) of coolant in its cooling system, though this can vary slightly by engine. Maintaining the correct coolant level and type is crucial for your Highlander's engine longevity and performance.

Quick Answer

• Total Cooling System Capacity: 9.0-9.5 quarts (8.5-9.0 Liters)
• OEM Coolant Spec: Toyota Super Long Life Coolant (SLLC) — Pink, HOAT (Hybrid Organic Acid Technology), Phosphated coolant.
• Mix Ratio: 50/50 Pre-diluted (do not add water if using pre-diluted, or mix 50/50 with distilled water if using concentrate).

Capacity by Engine Option

For the 2020 Toyota Highlander, the primary engine options and their approximate coolant capacities are:

Flush Interval

Toyota recommends the following coolant flush intervals for the 2020 Highlander using Toyota Super Long Life Coolant (SLLC):

• First change: Approximately 100,000 miles (160,000 km) or 10 years, whichever comes first.
• Subsequent changes: Every 50,000 miles (80,000 km) or 5 years, whichever comes first.

These intervals are general guidelines; if your vehicle is subjected to severe duty conditions (e.g., frequent towing, extreme temperatures, heavy stop-and-go traffic), more frequent checks and potentially earlier flushes may be advisable.

How to Refill & Bleed

Refilling and bleeding the cooling system on a 2020 Toyota Highlander typically involves these steps. Always ensure the engine is cool before working on the cooling system.

1. Drain the old coolant: With the engine cool, place a drain pan under the radiator. Open the radiator drain cock (petcock) at the bottom of the radiator. Remove the radiator cap to speed up draining.
2. Close drain cock & flush (optional): Once drained, close the drain cock. If flushing, fill with distilled water, run the engine with the heater on until warm, then drain again. Repeat until the water runs clear. This step is usually not needed when doing regular service with compatible coolant.
3. Refill with new coolant: Close the drain cock. Slowly fill the radiator with the correct 50/50 pre-diluted Toyota Super Long Life Coolant (SLLC) through the radiator fill neck. Fill the reservoir to the "FULL" line.
4. Bleed the system: This is crucial to remove air pockets. Start the engine with the radiator cap off and the heater set to full hot (highest temperature and fan speed). Squeeze the upper and lower radiator hoses several times to help dislodge air. As the engine warms, the thermostat will open, and the coolant level may drop; add more coolant as needed to keep it topped up.
5. Look for air bubbles: Continue running the engine until the cooling fan cycles on and off at least twice, and you no longer see air bubbles rising to the surface in the radiator. Install the radiator cap.
6. Final check: Drive the vehicle, then allow it to cool completely. Recheck the coolant level in the reservoir and add if necessary.

Note: The 2020 Highlander does not typically have external bleed screws on the engine. The self-bleeding design usually works well by repeatedly topping off the radiator and reservoir as described.

Common Cooling System Issues

While the 2020 Toyota Highlander is generally reliable, some common cooling system issues that can arise in this generation (or similar Toyota models) include:

• Water Pump Leaks: This is a known issue across various Toyota models with the 3.5L V6 engine, though typically more prevalent in earlier generations. Look for pink or dried crusty coolant residue near the front of the engine.
• Radiator Leaks: Over time, radiators can develop leaks, especially at the plastic end tanks. Keep an eye out for visible coolant puddles or a sweet odor.
• Thermostat Malfunctions: A failing thermostat can cause the engine to overheat (stuck closed) or run too cool (stuck open), leading to decreased efficiency and potential engine damage.
• Coolant Hoses: Hoses can degrade over time, leading to cracks, leaks, or blockages. Regularly inspect for swelling, hardening, or softness.
• Degraded Coolant: Neglecting coolant changes can lead to the coolant losing its protective properties, causing corrosion, scale buildup, and reducing the cooling system's efficiency.

Regular inspection and adherence to the recommended maintenance schedule will help prevent most cooling system problems.

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