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Discussion Starter #1
Measured the voltage across the battery at 12.24 volts. Put the negative probe across the top of the radiator, and get a reading of 12.54 volts.

Anyone know why the discrepancy?
 

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Galvanic action? If you measured with an old styleVOM bet you wouldnt see much if any voltage at all. A DVM is super sensitive to stray voltages due to its high impedance.
Wave the neg probe in the air.. whattya get? Put a test lite in parallel with your test leads, bet it reads zip or next to zip. The rad core isnt grounded to the frame, that I know of

Good observation, though. Bet grounding the rad core would have done away with a lot of water pump impeller probs in the Taurus 3.0L a few years back.

So, just to be anal, why not ground your core frame
 

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So, just to be anal, why not ground your core frame
I don't think that's being anal in this situation at all.

I'd look into why; either salt is eating the outside or the coolant is eating the inside; either one sux.
 

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Discussion Starter #4
Ran jumper wire from top of radiator to a ground connection on frame, voltage reading the same as across battery.

Should I make the jumper connection permanent?
 

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Your coolant has reached full electrolosys and is now chemically using your cooling system as a battery. Its time to flush it out, ground it, and possibly invest in a sacrificial anode before it eats something important, like your heater core.
 

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Put one positive lead inside of your Coolant solution without touching any metal edges, etc .. and the negative lead to ground. If it is reading 0.4 volts or higher, you need to flush your cooling system.
 

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Discussion Starter #7
I get a reading of 0.12 volts, with the positve lead in the coolant.

Using test strips, get a PH reading of 8.0.

Should I ground the radiator?

Is a zinc anode necessary, if so, where can I purchase one?
 

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I get a reading of 0.12 volts, with the positve lead in the coolant.

Using test strips, get a PH reading of 8.0.

Should I ground the radiator?

Is a zinc anode necessary, if so, where can I purchase one?
That's slightly alkaline. Do a flush.
And grounding that frame will do no good, I cant think of anywhere there's contact between it and the core, thus the coolant. If you want to do that run a small - 4/40 - brass bolt through the fins of the core and ground there.

D'OH! :facepalm: - never mind that italicized part. RalphP's right. Geezer brain fart, and totally WRONG.
BUT..
Bear in mind that could have the opposite effect you're going for... ie; completing an electrolysis circuit. you never can tell what eddy currents are going to do.

{by the way, I was an EE by vocation and have seen a lot of weird unintended stuff, esp in telecom and logic circuits}
- and once in a while would blow a meter by probing high volts on ohm scale.. addressing the brain fart issue. :rolleyes:
 

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That's slightly alkaline. Do a flush.
And grounding that frame will do no good, I cant think of anywhere there's contact between it and the core, thus the coolant. If you want to do that run a small - 4/40 - brass bolt through the fins of the core and ground there.
I do not know about the OP's car, but the radiator in my 5.0HO (a 1991) has these two tabs on the core that the fan shroud bolts to - work great as a grounding point.

I think that's where Splattered did his 4.6's radiator ground.

Worth looking at.

RwP
 

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The activation energy to eat the aluminum is ~.4; as log as you don't see that, you're ok.

That said, I'd flush it, and replace the coolant. It's only going to get worse.

Alkaline is actually slightly worse for aluminum; but don't add anything to match the pH, as that would be worse.

Adding a zinc anode is as far as I would go.
 

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And grounding that frame will do no good, I cant think of anywhere there's contact between it and the core, thus the coolant. If you want to do that run a small - 4/40 - brass bolt through the fins of the core and ground there.

D'OH! :facepalm: - never mind that italicized part. RalphP's right. Geezer brain fart, and totally WRONG.
*snicker*

ET's been doing that to you EEs since Tesla invented electricity :diablo:








































(Just ragging - I know what you were thinking, and really didn't know if all radiators had those clips up there.)
 

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*snicker*

ET's been doing that to you EEs since Tesla invented electricity :diablo:
Actually, it's WORSE! I'm trying to figure out what I was referencing in my mental image. I've only had 4 cars {3 Birds and a Taurus} with that plastic tank style radiator, replaced THREE plus a water pump, separately.
I know full well how the dang thing's constructed. And the clip has nothing to do with it.
 
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