Electrolysis
Electrolysis has been getting some play in the trade press recently!
True electrolysis in engine cooling systems is rare, and often missed. When it does happen, failure occurs quickly.
In this experiment (ASTM D6208) electrolysis is induced between a sample of radiator material and a cathode, passing electricity through the coolant. When this happens, the radiator material is damaged. The ability of a coolant to protect the metal is measured, but it only takes 2 hours in this experiment to do a lot of damage!
A properly operating car or truck engine obviously has a lot of active current flowing through various components as they do their job. In automotive systems, the current returns to the battery through system grounds.
These grounds offer a path of least resistance for the current, and although a trace current may stray through alternate paths, it is usually not enough to destroy anything in the vehicle in its normal lifetime
If something happens to the grounds, the current will seek the next-best path to ground and to the battery. This next best path can include taking a short-cut through the coolant.
When this happens, the current degrades metals, often in the radiator, in a process known as electrolysis.
Components involved in electrolysis can fail very quickly, in days and weeks, as opposed to corrosion damage that takes months or years to destroy a component!
Electrolysis is less common than corrosion and many other problems, so it is often missed by repair people until the same vehicle returns time after time with expensive radiators leaking.
Once diagnosed, the faulty ground must be identified and repaired to restore proper operation and durability of the affected components.
