^malabo ba ang mata mo?

To discern much clearer you can light up the reservoir

If you inspect the reservoir it has a hole on top known as overflow port. The purpose of that port is to provide a channel to release pressure. When the engine is running its burning fuel and that generates heat. A rise in temperature is coupled with an increase in pressure in the reservoir. As pressure gets stronger it will push some of those coolant fluid out otherwise the pressure could build strong enough to pop open the reservoir cover

Sent from my SM-A520W using Tapatalk