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Electrolysis and your cooling system


A vehicle has many electrical circuits. For an electrical component to function properly, the electricity must return to the source through the ground side of the circuit. Ground paths are usually metal conductors such as wires or the vehicle frame, engine or body.
Poor ground paths, such as broken wires or corroded connections, will cause the electrical flow to seek another path back to the battery, and coolant is a good conductor. But if the coolant is acting as a conductor, system damage will often occur.
Electrolysis refers to the changing of a chemical solution by passing an electric current through it. Excessive voltage passing through engine coolant can change its chemical structure and reduce its effectiveness.
Electrically-charged fluids damage metal too, so components such as the radiator, heater core and water pump are at risk. This type of damage begins from the inside and works outward; it is rarely seen until a leak appears.  Always consider electrolysis as a possible contributor to the failure of a metal component, particularly if unexplained flaking or corrosion is present.
When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.
You can E-mail us at or visit to find a Mobile Air Conditioning Society repair shop in your area. Visit to find out more about your car’s mobile A/C and engine cooling system.
 Many thanks to MACS member Spectra Premium Industries for the photo of electrolysis damage.

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