Are you guys grounding your aluminium radiators?
09-28-2009, 04:20 PM
#1
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Are you guys grounding your aluminium radiators?
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09-28-2009, 05:11 PM
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Betcha the radiator was filled with antifreeze plus tap water instead of antifreeze plus distilled water. The tap water down here will eat through the copper pipes in your house in the first ten to fifteen years. After that they replumb it with pvc.
Dissolved minerals in tap water = electrochemical reaction between dissimilar metals. That is as basic as the two plates stuck in a lemon making electricity. Anybody with a saltwater boat should have a story or two to tell about this phenomenon, too.
Dissolved minerals in tap water = electrochemical reaction between dissimilar metals. That is as basic as the two plates stuck in a lemon making electricity. Anybody with a saltwater boat should have a story or two to tell about this phenomenon, too.
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09-28-2009, 05:32 PM
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uhm, wouldn't grounding the radiator accelerate electrolysis?
take a voltmeter, open rad cap and hold the + lead in the coolant. put the - lead to ground. report findings.
take a voltmeter, open rad cap and hold the + lead in the coolant. put the - lead to ground. report findings.
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09-28-2009, 05:52 PM
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I was just about to say the same thing. If two dissimilar metals are isolated from one another except by the electrolyte solution, then no current will circulate between them.
And yeah, pure distilled water, plus glycol, should be a pretty ****-poor electrolyte.
From the site linked to in the M.n posting:
Skip Cannon correctly refutes this asinine idea by quoting the following:
And no, it isn't a conspiracy to force everyone to buy new radiators.
There's no such thing as a "difference" in current. You can have a difference in voltage potential, and if two members with different potentials are connected via a conductive path (such as a ground strap), then you will have current flow.
Think about a simple battery. You have two plates of different material, bathed in electrolyte. Between the two plates there is a difference in voltage potential, but no current flows. It's not until you attach a load between the two plates that you get a flow of current.
And yeah, pure distilled water, plus glycol, should be a pretty ****-poor electrolyte.
From the site linked to in the M.n posting:
In cases of electrolysis, a defective or missing ground on an electrical device causes the electricity to seek the path of least resistance whenever the component is energized. Sometimes the path of least resistance is a radiator or heater hose, or the radiator or heater core. As the current draw of the poorly grounded accessory increases, so does the destructiveness of electrolysis.
Ok, so first off, this presupposes that the heater core or radiator represent a path to ground. In the Miata (and most other modern automobiles) neither one of these are connected to ground in any way. Skip Cannon correctly refutes this asinine idea by quoting the following:
Early on, when electrolysis first cropped up as a problem in cooling systems, many mechanics attempted to solve the problem by grounding the heater or radiator in order to "collect" any stray voltage and route it to battery ground. But mechanics soon discovered that grounding a heat exchanger to "collect" stray current merely accelerated the damage to the heat exchanger.
The thing is, with pretty much every modern automobile using an aluminum radiator these days, and a pretty large number of 'em still shipping with iron blocks, how many OEMs do you see attaching ground straps or hanging sacrificial zinc anodes inside the cooling system, or other such insanity? And no, it isn't a conspiracy to force everyone to buy new radiators.
Think about a simple battery. You have two plates of different material, bathed in electrolyte. Between the two plates there is a difference in voltage potential, but no current flows. It's not until you attach a load between the two plates that you get a flow of current.
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09-28-2009, 06:08 PM
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Think about a simple battery. You have two plates of different material, bathed in electrolyte. Between the two plates there is a difference in voltage potential, but no current flows. It's not until you attach a load between the two plates that you get a flow of current.
That makes sense.
Then let me ask you this; why do you think Vanagons were so likely to corrode inbetween the cylinders and the heads (they are both aluminum)? A sacrificial anode did away with this problem. In that case, the engine is well-grounded, but those engines were expected to fail about every 80K miles, due to corrosion.
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09-28-2009, 06:11 PM
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That makes sense.
Then let me ask you this; why do you think Vanagons were so likely to corrode inbetween the cylinders and the heads (they are both aluminum)? A sacrificial anode did away with this problem. In that case, the engine is well-grounded, but those engines were expected to fail about every 80K miles, due to corrosion.
Then let me ask you this; why do you think Vanagons were so likely to corrode inbetween the cylinders and the heads (they are both aluminum)? A sacrificial anode did away with this problem. In that case, the engine is well-grounded, but those engines were expected to fail about every 80K miles, due to corrosion.
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09-28-2009, 06:41 PM
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Seriously though, I'm not intimately familiar with the wasserboxers, as I only ever owned Beetles.
Were the cylinders in fact the same material as the heads? The engine case itself was made from a high magnesium alloy, and I always assumed that the jugs were as well.
Of course, they've got steel liners in them, not sure if that's part of the equation. (Were the liners wet? I've never seen one removed.)
If I recall, the wassers did use head gaskets. Possible contributor?
Too many variables, and my knowledge of that particular engine is pretty limited. On the other hand, consider that those long studs, going all the way from the head, through the jugs and into the case, is electrically similar to a ground strap.
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