Sisirit ang tubig when the engine is running because of the water pump.

Even if the engine is off, kung mainit naman siya, sisisrit pa din ang tubig.

Kung overheat and you are refilling, umaandar ang engine so that the new and old water will mix evenly (walang cold and hot spots).

Before opening the radiator cap of a hot engine, put a soaked rag on top, partially open to relieve pressure, then remove cap after pressure has been relieved.