The zinc block is a "sacrificial anode". This is a technique known as "cathodic protection".

The terms anode and cathode just refer to the flow of elecricity. In a galvanic cell, the electrons flow from anode to cathode.

The ph of the coolant is VERY important because as it becomes more acidic, it will conduct electricity better! A ph of 7 will not conduct electricity.

The anode will oxidize as part of the electrochemical process. So it's helpful to think of a sacrificial anode (often Zinc) as sacrificially "steering" the corrosion to itself, thereby protecting the iron or other vulnerable parts.

justin

 

Your right HOHN, jrs_dodge_diesel, rowilson

But it would be easier to just change your coolant when its time or earlier than worrying about ph level, minerals, zincs, etc.

When your done you know your CTD going to make it through the winter and NOT freeze up.

I understand why some of you are very religious about distilled water... (ph levels and minerals)... This just insures that your expensive radiator is not going to get damaged from the inside from the two enemies above.

Like everything else it just better to dump and change the fluids of your truck early or offen than to say "It looks OK!" You never know what has settled to the bottom of your oil pan, radiator, transmission, etc.