Your coolant reservoir tank should be at least 30% full. Most reservoir tank has min and max mark drawn on the side of the container. What is this? The most common cause of a coolant leak is a bad radiator cap, bad radiator fans, and loose radiator hose clamps.

Is it bad to overfill coolant reservoir?

Coolant expands as it heats and contracts when it cools. The extra space prevents damage to your engine and hoses. ... In worst case scenarios, overfilling your antifreeze tank can lead to electrical damage if overflow comes into contact with engine wiring.

Why is my radiator overflow full?

Coolant, or antifreeze, is essential to regulating the temperature of your vehicle. It's also extremely toxic and designed to stay inside a closed system. If you're seeing an overflow, it could be due to a radiator cap, thermostat, water pump, or radiator malfunction.