What Is Electrolysis?
Electrolysis is the result of electricity flowing through your cooling system and causing an electrochemical charge across the aluminum. This results in rapid corrosion and severe damage to the components in your cooling system including discoloration, pitting, flaking, and pinholes.
Most common in late model vehicles, hot rods, and street rods, electrolysis will usually occur if there is a defective or missing ground on one of the numerous potential electrical sources.
How Can I Test For It?
To test if your cooling system has been affected by electrolysis, you will need a volt/ohm meter.
- Connect the negative lead of the meter to the battery ground.
- Carefully insert the positive lead into the coolant inside the radiator without contacting the filler neck.
- Check the Result: If the reading is more than 0.10 V, there is an electrical current flowing through the system.
- Continue to check voltage between the coolant and the engine.
- Check voltage between the coolant and the frame.
- Repeat the test with the positive lead touching the radiator core instead of the coolant.
Pro Tip: Isolate the Source
Conduct this test with the engine running and all accessories on. Have a friend systematically switch components (lights, fans, A/C) on and off while you monitor the meter. If voltage drops when disconnecting a specific circuit, you have found the faulty source.
Ways to Prevent Electrolysis
Unfortunately, only careful monitoring and proper maintenance can prevent electrolysis from destroying your system.
- ALWAYS ensure the radiator is NOT used as a ground.
- Ensure all electrical components are grounded properly to the chassis or engine, never the core support.
- Periodically test your system using the steps above.
- Check for discoloration or pinholes, especially around tube-to-header joints and near electric fan mounts.