Thanks to our Partner, Pico Technology

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Matt goes down a rabbit hole on the science of bubbles and comes back with something surprisingly practical: cavitation is a major source of cooling-system component damage, especially in and around water pumps. The “bad guy” isn’t the bubble forming—it’s the bubble collapsing, releasing intense localized energy, micro-jetting, and shock waves that pit and erode metal surfaces over time. The takeaway: approach cooling-system maintenance as anti-cavitation prevention, not just “keep it from overheating.”

Key topics covered

Why cavitation damage is often misattributed to electrolysis (and what’s actually happening)

The real destruction mechanism:

1. Bubble collapse → extreme localized heat (doesn’t “cook” the system, but signals energy density)
2. Micro-jet stream through the collapsing bubble “donut” → pitting/erosion
3. Shock wave effects (ties into why ultrasonic cleaning works)

How bubbles form even in a pressurized cooling system

1. Localized low-pressure zones behind an impeller blade
2. Pressure drops along surfaces and restrictions (design or contamination-caused)

Why “radiator cap” is a misleading name

1. Better term: degassing cap
2. It maintains system pressure (key to preventing local boiling) and “burps” gas/vapor out

Coolant chemistry isn’t just freeze/boil protection

1. The inhibitor package forms a protective barrier on internal surfaces that absorbs cavitation attack
2. Over time that protection depletes → cavitation damage shows up

Water quality matters more than most people think

1. Minerals/impurities can create deposits → restrictions → pressure drop zones → bubbles
2. Contamination can also become nucleation points for bubble formation
3. Distilled/RO water or properly formulated premix is the safer play

“Universal coolant” skepticism

1. Use proper coolant type for the application—chemistry and inhibitor packages matter

Practical takeaways for shops

Start treating cooling-system service as evidence-based prevention

Testing and inspection that should be part of regular maintenance:

1. Degassing cap pressure test (rated pressure matters)
2. Coolant concentration (ideally with a refractometer/hydro refractometer)
3. pH testing (imperfect, but can hint at inhibitor depletion)
4. Voltage potential test with a DMM (if present, verify grounds and consider additive depletion as a possible indicator)

Recommend coolant replacement based on:

1. Test results you can measure + time/mileage intervals (what you can justify)

Customer communication angle (the “why they should care”)

A simple way to explain it without going full science-documentary:

1. “Coolant doesn’t just prevent freezing and overheating—it protects the inside of the cooling system.”
2. “Over time the protective chemistry wears out, and tiny vapor bubbles can collapse and pit metal surfaces.”
3. “We’re restoring protection, verifying pressure control, and preventing long-term erosion.”

Memorable moments / quotables

1. “It’s not the bubble forming—it’s the collapse.”
2. “We don’t think about cooling-system maintenance from an anti-cavitation point of view.”
3. “We should stop calling it a radiator cap… it’s a degassing cap.”

Thanks to our Partner, Pico Technology

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Contact Information

1. Email Matt: [email protected]
2. Diagnosing the Aftermarket A - Z YouTube Channel
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