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Automotive Electrolysis ... is there any hope?

Dealing with the effects of Automotive Electrolysis can be a very aggravating. It is a cruel and demanding teacher, and has a steep learning curve. 


However YES, there is hope! The good news is that Automotive Electrolysis is governed by the laws of physics, and behaves in predictable ways. If we can understand a bit about how it works, we will be able to get the upper hand on this problem, stop it in it's tracks, and send it packing .
Please continue reading and learning about Electrolysis on our continually updated knowledgebase located here: VoltageDrop. You will find articles, photos, how-to's and products designed specifically for helping you survive your exposure to Electrolysis. Whether you are an Automotive Repair Shop, Feet Service Coordinator, or an Individual Vehicle Owner, the solutions to you Electrolysis Problems are known, published, and available.
Electrolysis Knowledgebase located here: VoltageDrop.




According to the dictionary, electrolysis is:

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




What is electrolysis and why is it a problem in an automotive cooling system? Lets start by trying to understand electrolysis as it pertains to automobiles. Electrolysis is a destructive force that packs enormous potential to damage not just cooling system components, but any aluminum engine part that has contact with the coolant. The coolant acts as both the catalyst and as the conductor, just like the electrolyte in a battery. The "electrodes" mentioned in the above definition are the aluminum components in the cooling system (like the 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. Generally you won't know you have an electrolysis problem unless you have (a series of) unexplained leaks. However, to add yet another factor, in some parts of the country (southwest), electrolysis is much more prevalent than others.

Fact #1 Electrolysis will manifest itself with unexplained coolant leaks in thin walled aluminum components, typically the heater or radiator, whichever may be electrically more attractive to the ion movement.

Can electrolysis be measured? At the heart of the electrolysis issue is it's measurement. If it can be measured, it's presence can be verified, which is extremely important when we are removing the electrolysis. More than half a volt!

It is a simple measurement, a digital VOM is needed, simply attach one lead to the negative battery post, and with the other, dip it in the coolant. Should read zero right? Maybe just a bad ground? Try this, remove a battery post. Still reading .3v or above? It's not a loose ground your after.... You better keep reading.

Fact #2 If you have a reading of more than .3v, (three tenths), you have electrolysis. Generally, a reading of hundredths (.01-.09v) is below the action level, and will not result in aluminum failure.

Can Electrolysis be prevented? Absolutely! The key to the prevention of electrolysis is to understand the cycle. If we can remove the electrolyte, the process can not occur. But isn't the electrolyte the same thing as the coolant? Yes, and no.

Fact #3 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? In the early '90's the recommended service interval for coolant was 24 months. When changed at this interval, the coolant was removed before it was "spent". It 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, electrolysis in the early 90's was extremely rare.3 Beginning in 1996, with the introduction of Dex-cool, the recommended service interval of coolant grew to 5 years. New developments in chemicals 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. Another factor is the increasingly tighter environmental restrictions on flushing and disposal of automotive flush water. "Can't just flush'er out like we used to do".

Fact #4 Longer maintenance cycles allow the coolant time to decompose, loose it's protection, and get acidic. As the existing metals in the cooling system are now "exposed" to an increasingly strong electrolyte, ion movement begins to occur. Ion particles are whisked away by the fast flowing coolant,
This stuff is packin' almost .6v

the block, so that even when the coolant is finally changed, the acidic nature remains. Too little too late.

Fact #5 If you want to prevent electrolysis from taking hold, the time proven flush and fill is all that is needed, as long it done before coolant decomposition begins. However, once electrolysis has taken hold, a simple flush and fill just isn't enough, and more drastic measures are called for.

How do we get rid of electrolysis? Since automotive 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. We first pull the thermostat out, connect our flush machine4 and let run. Sometimes we flush for as long as 36 hours. Once the flushing and rinsing is complete, new antifreeze and fresh water (50/50 mix) is installed with a new thermostat. Generally distilled water is not used, as it tends to be "hungry water" looking for ions. A chemical additive is then added to help in a variety of ways. It will control pH, help the coolant to remain non conductive, and contains an oxygen scavenger to prevent cavitations, erosions, and pitting. Last but not least, a sacrificial anode is introduced into the cooling system to "pull" any stray electrolysis away from aluminum components. Don't forget to retest for voltage in your cooling system. If you have more than .1v (one tenth), your not done flushing! For access to these electrolysis products click here.

There are plenty of good uses for electrolysis, such as in the plating industry, where the goal is to move metal particles from one surface to another. Gold plated emblems and jewelry are successful applications of electrolysis. Of course another type of electrolysis is hair removal. Altogether different, and discussed here. Industrial applications of electrolysis include the manufacture of aluminum, and lithium, and hydrogen for hydrogen fuel cell vehicles. Other commercial applications include the manufacture of aspirin. But in an automobile cooling system, electrolysis will only give us a headache!

If electrolysis has always been around, why is it such a big problem now? It used to be that the difficult electrical problems consisted of shorts, opens, and draws. Now we have to worry about reference voltage, bus speed, and thermo resistors. Secondary spark voltages are only increasing, A/C and D/C currents and EFI signal amplitudes add an aggressive neutron and proton cocktail where water conducts electricity by the movement of ions in the increasingly at-risk cooling system. In an unprotected cooling system these neutron and proton atoms magnify the strength of the electrolyte infected coolant. 2 With more and more aluminum components under the hood, and in the cooling system, longer maintenance cycles and more stray electrical energy, it's no wonder it's a problem.

Additional resources.

How to lose a customer is a informative article written for the automotive repair shop dealing with the electrolysis issue. In addition to the technical aspects of electrolysis, it touches on the warranty issues of failed parts due to damage caused by the electrolysis. "If only I had read this first....."

Improper coolant a short informational sheet from Performance Radiator discussing the proper coolant and water requirements.

Electrolysis problems increase is a short reprint article covering the highlights of electrolysis detection and repair.

Electrolysis pictures pictures taken of vehicles at our shop that have experienced electrolysis related failures, and repairs.


1 The American HeritageĀ® Dictionary of the English Language, Fourth Edition
2 BMR Distributing Interject Electrolysis Arrestor.
3 Speaking for our experience at San Carlos Radiator.
4 Proprietary process.