Rudolfo,<P> With regards to coolant, the coolant has to be mixed with water to achieve the maximum benefit of its properties. Coolant is designed to stabilise the cooling system. It prevents problems of scaling caused by running plain water in mixed metal cooling systems (iron engine block, aluminum heads, and brass in the radiator). It also provides a safety margin on those cold nights when water would freeze and expand in the block pushing out frost plugs and possibly cracking the block. Up here in Canada we mix it 50% water and 50% antifreeze which prevents the water in the system from freezing to about -40 centigrade. I also spent a lot of time in the middle east where we also used antifreeze in a 60% water/ 40% antifreeze. It helped keep the engine from overheating as the ethylene glycol helps the water in the cooling process. Are you using any antifreeze in your cooling system? If not I would suggest strongly that you do. Hope this helps<P>Gord