buknoy, hindi naman mag overheat yung sasakyan pag walang coolant (only water). most jeepney hindi naman gumagamit ng coolant pero hindi naman nag ooverheat. kahit nga yung lancer box type namin hindi din nag overheat kahit distilled water lang gamit namin.

alnr, best thing to do is to check your owner's manual. depende din kasi kung ilan yung laman ng radiator sa sasakyan mo. or pwede din drain mo yung laman ng radiator then fill it with water by liter. para ma measure mo ilang liter ang kasya. then drain the water again and this time fill it with 50/50 mixture of coolant and distilled water. what i did before was I use an empty 1 liter bottle then fill half a liter of distilled water and half a liter of coolant. then saka ko binuhos sa radiator until mapuno yung radiator and sa max ng reservoir.