Dear customer,
You can use car coolant instead of water, and coolant works better for cooling, anti‑corrosion, and anti‑freezing.
Coolant is more effective: it improves cooling stability, protects the internal water tank from rust, and prevents freezing in low temperatures.
The product page does NOT mention a visible external fill line on the cooling water tank. We recommend adding liquid slowly and not overfilling.
Best regards
By vevor
