Check your antifreeze using this one weird trick (genius!)

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Check your antifreeze using this one weird trick (genius!)

Post by Lee »

Well, it might be genius if it’s scientifically sound, but I have my doubts. Anyway, I was intrigued enough to try it.

In this Rockauto newsletter, scroll down until you see the heading “Testing Coolant”, and you’ll see a simple procedure for measuring electrolysis voltage with a high impedance voltmeter. ... l#tomStory

So I tried this on my ‘62 (coolant changed last year), my ‘41 (roughly 3 years), and the ‘68 (too many years to remember - at least 10). Here’s the results:
Anyway, there appears to be a correlation with the coolant age in my cars. Dan, you’re the double E, what do you say?
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Re: Check your antifreeze using this one weird trick (genius!)

Post by tomo »

Lee, if the coolant gets too acidic, you can have galvanic corrosion and it will develop a small voltage difference between the coolant and the metals around it.
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Re: Check your antifreeze using this one weird trick (genius!)

Post by Dan Szwarc »

I’m a EE, not a chemistry major. Electrolytic corrosion is not my specialty.
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Re: Check your antifreeze using this one weird trick (genius!)

Post by TonyC »

Something the writer failed to mention, which even I did not think about until I experienced it two years ago with the rebuild. Debris in the radiator is a small concern compared to debris in the block, which will happen after five or six decades. I discovered such a buildup that the coolant inside the block would not even come out when I removed the drain plugs in the block. After breaking through that, I removed enough deposits to choke off half the passages inside the block, and it was so thick that not even straight-up hot-tanking would get rid of it. I had to probe hard and heavy into the block to break it all up before I could even send the block out for hot-tanking.

If this happened to me, it can happen to others, so I'm giving this bit of advice free of charge. If doing a coolant change, unscrew the drain plugs (both of them) from the block and observe the coolant flow. If there isn't any, or if it seems to drip out as opposed to flowing out, you have blockage that needs to be removed. I would even dare say that this can happen with any engine regardless of make that is old enough and not given regular full flushes. That will usually mean full rebuild, but a few days of probing with a thick wire and a lot of stubbornness can help remove much of that buildup if you can't or don't want to commit to a full rebuild. Leaving those deposits in there has to contribute not only to coolant starvation of the block but also coolant degradation, resulting in corrosion problems.

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