"When the antifreeze/coolant wears out, it
acts like the acid in a battery, allowing dissimilar metals to
react, and create a voltage."
According to the dictionary, electrolysis
1) Chemical change, especially decomposition, that is
produced in an electrolyte by an electric current.1
2) An electrochemical process by which electrical energy is
used to promote chemical reactions that occur at electrodes.2
Type B electrolysis is similar to the dynamic of a
battery. The coolant acts like a catalyst and allows and encourages ion
movement, just like the electrolyte in a battery. The "electrodes"
defined at the top of the page, are the aluminum components in the
cooling system (like the lead plates in a battery). The "electrochemical
process" mentioned is the aluminum particle (ion) movement, such that
leaks (thinning of wall surface) occur. When enough ions have moved,
this results in a failure (leak) typically in the radiator or heater
due to the thickness (read thinness) of the tube wall surface. A thicker
surface (like an aluminum casting) is not more resistant to
electrolysis, but is not as likely to leak because it is thicker.
However these thicker surfaces may leak anyway if the electrolysis
occurs at a gasket surface.3 Generally you won't know you have an
electrolysis problem unless you have (a series of) unexplained leaks.
Electrolysis will manifest itself with unexplained coolant leaks in thin
walled aluminum components, typically the heater or radiator, whichever
may be more "electrically attractive" to the ion movement.
When the coolant gets acidic will it act like an
electrolyte, and set the stage is set for
electrolysis to occur, and the destruction of thin aluminum components to begin.
So how does coolant get acidic? Up until the mid '90's, the recommended service
interval for coolant was 24 months. When changed at this interval, the coolant
was removed before it was
still had good color and was still protecting the metals with corrosion
inhibitors. When changed, all the old coolant mix was purged, along with any
small amounts of acidic build up. As a result, Type B electrolysis in the early
90's was extremely rare. Beginning in 1996, with GM's introduction of Dex-cool,
the recommended service interval of coolant grew to
5 years. GM
wasn't the only automaker to use longer life coolants. New developments in
coolant chemistry and a changing maintenance strategy has fueled these advances
that are tested in laboratory conditions and on vehicle fleets. Unfortunately
the successes in the laboratory have not always directly translated to a success
in the field. It is not surprising that electrolysis is now a major under hood
problem.4 Another factor is the increasingly tighter environmental restrictions
on flushing and disposal of automotive flush water.
How do we get rid of electrolysis?
Since Type B electrolysis is a chemical problem as mentioned
above, the answer to ridding ourselves of this problem will be to
neutralize the acid. In addition we need to remove the spent
antifreeze, remove any metal particles
in the deep reaches of the
engine block, and "scrub" the internal surfaces of the block. Sound
like a flush to me. But not just any flush. We need to REALLY flush
this thing out. Flushing options include chemical flush,
mechanical flush, or a "freeway flush". Chemical flushing involves adding
The Flusher to
our vehicle and running the engine for 1-3 hours. Driving at freeway
speed is highly recommended. Once we have completed that cycle,
draining and refilling with water 2-3 times generally will provide
decent results. The next step is to add fresh coolant and
Arrestor. The final addition is to install
The Anode to our system.
If the cooling system has trouble getting clean,
The Coolant Filter
can be an important tool to pull out particulates. Mechanical
flushing involves a machine that continually circulates a
chemical solution through the engine and hoses and heater. We first
pull the thermostat out, connect our flush machine5 and let it run. Sometimes
we flush for as long as 36 hours. Once the flushing and rinsing is
complete, new antifreeze,
Arrestor, and fresh water (50/50 mix)
is installed with a new thermostat. Finally The Anode is installed.
Generally distilled water is not used, as it tends to be "hungry
water" looking for ions, creating more problems that it solves. For
access to these electrolysis products,
Summary: I suggest a three prong approach. 1)
Treat the problem in place (The Flush). 2) Distract your adversary
(The Anode). 3) Chemically suppress any "bounce back" (The Arrestor). It's
as easy as One-Two-Three.
Or, you could just replace the engine for
a few thousand dollars.....
For in an in depth article on flushing cooling
systems, and in particular electrolysis flushing,
The American Heritage®
Dictionary of the English Language, Fourth Edition 3 Remember the
Intake Manifolds on late '70's Cad Seville? 4 Speaking for our
experience at San Carlos Radiator. 5 Proprietary process.