hai betacam.
no doubt, plain water is the cheapest kind of coolant. ha ha ha
but remember, plain water when mixed with air can convert metal into rust. when u mix coolant, the chances are reduced almost completely.
from what i heard (becoz not proven yet), it is not necessary to buy coolant with anti freeze and anti rust mixture. especially anti rust as they are corrosive and may caused water pump leak under long term use.
u may use radiator flush to clean water jackets (inside engine block) for temporary which is good enuff to remove unwanted residues. then juz get a normal coolant from ur accesory shop and add into radiator. for kancil, a can may do good. for saga, one and a half, while bigger cars advisable to mix 2 cans.
DO NOT add too much coolant also, there are no additional benefits. 1 can coolant may be adequate but over filling it (5 or 6 cans) may result the coolant becoming corrosive.
its a good thing to have coolant as the colour (green or blue) will tell u when there is leak. for example, when u wake up in the morning and before u start ur car u noticed there is green water on the garage floor. straight away u know something is not rite, cooling system may need to be inspected and it is advisable not to drive the car for long disatnce where damage can occur to the engine.
one good coolant i can recommend to all of us is Toyota Long Life Coolant. it is red in colour but turns black (not blackie) when the time comes to replenish. normally at 40,000km. or average 2 years normal driving. coolant also acts as a lubricant for the water pump.
hope all this will help.
