One cannot judge the condition of the coolant by how it looks. Another problem not detected by appearance is the concentration of antifreeze in the coolant. One in three vehicles have either too much water or too much antifreeze in their coolant mix. The long-term effects of coolant problems can be detrimental to a vehicle s overall condition. Coolant neglect causes corroded and clogged radiators, eroded aluminum cylinder heads, eroded water pumps and thermostat housings, rotted radiator hoses, leaky heater cores and freeze plugs, blown head gaskets and chronic overheating.
Straight water provides no freezing, boilover or corrosion protection.
Straight antifreeze cannot be used without mixing it with water to lower the freezing point of the solution. It is best to use distilled water because it is pH neutral, contains no acids, dissolved salts or minerals and maximizes the coolant life. In order to know whether the coolant is accurately mixed, one needs to measure the strength or concentration of antifreeze. If the extra antifreeze is just added in, one could add too much, which would clog the radiator and reduce heat transfer. To ensure a proper coolant change, you must flush out the system to get rid of all the old coolant, clean out the system and then refill it with a correctly balanced mix of distilled water and fresh antifreeze.