ARCHIVE Wits' End- I really hate galvanic corrosion
- Thread starter NLXTACY
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WarDamnEagle
SILVER Star
Ever heard of galvanic corrosion? Well after seeing what kind of damage it can do inside of our engines, I decided I really needed to do something about it.
Here is the start of what will be a solution for all 80 series owners and right after, 100 owners. Corrosion is a huge issue especially if you have an aluminum radiator.
One way to remedy it is to use a sacrificial anode. In this case zinc because it’s a less noble metal. With the coolant flowing (the electrolyte) ions will always try to pull electrons from weaker dissimilar metals. In our case, aluminum. Well introducing zinc makes the ions favor corroding the zinc instead of aluminum.
Right now this piece is ready but I still need to ground it for those with plastic tanks. Almost there.
Feedback welcome. I feel like I'm missing something but I'm not sure what it is
Apologies in advance if I'm being overly pedantic but you did ask for feedback. I think most of the corrosion in our cooling system is electrolytic corrosion and not galvanic corrosion - just my opinion. Maybe what you are trying to do is to introduce galvanic corrosion to protect those parts that would normally corrode from electrolytic corrosion? Not trying to mince words with you but I think for your solution to work you need to "love galvanic corrosion".
Lastly, still not sure about the above the highlighted statement. I see deposits on the aluminum radiator in your first photo but I'm not sure that's "corrosion". Again, the radiator should oxidize over and that should end any further corrosion of the underlying metal. I don't recall seeing a lot or maybe not any posts of someone's aluminum radiator suddenly springing a leak from internal (or external for that matter) corrosion.
Good luck with the project. You should weigh the zinc anode before you install it. Might help with data collection when you pull it to check status.
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A lot of boats use annodes. They sell various metal annodes for boat hulls, prop shafts, stern drives, etc
That's a whole market for boat annodes. I thought it was a marine thing?
That's a whole market for boat annodes. I thought it was a marine thing?
Seems like cheap insurance?
The paradox that the people buying this are too maintenance-anal to need it, may be the real issue.
Then again, need is such a justifiable term...
Maybe as a gift for that clueless Cruiser friend who never touches their truck?
just know, it's a thing. @NLXTACY 's not just pulling a gold-anodized plug out his rear. (although if you did, I would probably buy it)
www.mechanic.com.au
*I remember meeting a Alfa Romeo nut, he had a set of NOS Sparco/Alfa magnesium racing wheels from the 60s on display...with holes in the rim.
lead weights ate right through over the years. Galvanic corrosion. Sad.
The paradox that the people buying this are too maintenance-anal to need it, may be the real issue.
Then again, need is such a justifiable term...
Maybe as a gift for that clueless Cruiser friend who never touches their truck?
just know, it's a thing. @NLXTACY 's not just pulling a gold-anodized plug out his rear. (although if you did, I would probably buy it)
Electrolytic Corrosion in Radiators Demystified
www.mechanic.com.au
*I remember meeting a Alfa Romeo nut, he had a set of NOS Sparco/Alfa magnesium racing wheels from the 60s on display...with holes in the rim.
lead weights ate right through over the years. Galvanic corrosion. Sad.
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WarDamnEagle
SILVER Star
Seems like cheap insurance?
The paradox that the people buying this are too maintenance-anal to need it, may be the real issue.
Then again, need is such a justifiable term...
Maybe as a gift for that clueless Cruiser friend who never touches their truck?
just know, it's a thing. @NLXTACY 's not just pulling a gold-anodized plug out his rear. (although if you did, I would probably buy it)
Electrolytic Corrosion in Radiators Demystified
From your article on electrolytic corrosion in radiators (note: not galvanic corrosion):
Electrolytic corrosion must not be confused with galvanic corrosion, which occurs when two dissimilar metals, such as the aluminium and cast iron in car engines, come into direct contact with each other. Galvanic corrosion depends on the difference in electrical potential of each metal, and while stray electrical currents can accelerate the process of galvanic corrosion, this form of corrosion does not require the presence of an electrical current to occur.
I'm not smart enough to discuss this, other than reference articles, obviously.
But in similar conditions, why do they use anodes in radiators then? I know this is not a made-up thing.
I've seen them sold for auto use.
*if it's electrolysis or galvanic, it's still corrosion. Maybe it's just misuse of the term that's confusing?
*not arguing @WarDamnEagle - i may be ignorant on something I know about in passing
But in similar conditions, why do they use anodes in radiators then? I know this is not a made-up thing.
I've seen them sold for auto use.
*if it's electrolysis or galvanic, it's still corrosion. Maybe it's just misuse of the term that's confusing?
*not arguing @WarDamnEagle - i may be ignorant on something I know about in passing
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WarDamnEagle
SILVER Star
No argument here; just a discussion. It's not a subject I have deep knowledge of either; probably just enough to be dangerous.
I think the usage of anodes is much more common in marine use as salt water is quite conductive and thus enables galvanic corrosion between dissimilar metals much more so than a 50:50 mix of water and antifreeze (even tap water is considerably less conductive). I also think corrosion in general is a bigger problem with copper than with aluminum as copper doesn't oxidize (corrodide) to a relatively inert state the way the surface of aluminum does. Lots of radiators are copper core. Remember also, just because it's sold doesn't mean it's actually worthwhile to use.
As an aside, I have an FJ55 with quite a few chrome parts. Once that chrome gets breached with even a tiny pinhole galvanic corrosion sets in and the base metal corrodes away to nothing pretty quickly; much quicker than it would if just left to rust on its own. That's why used, intact FJ55 license plate lights are all but non-existent.
ppc
M Go Blue
That is why marine manufacturers like Mercury Marine around 2000 went to closed cooling systems in their inboards versus pumping seawater through the entire motor.
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Why not? Put sunglasses on?
Its much better anode, it will protect your aluminum radiator much better than Zn
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Home water heaters have a big sacrificial anode for the same reason, that is supposed to get changed every couple of years. Of course, if you're like me, you put in a new heater, nod your head and say yeah, yeah...and pretty soon 10 years go by...oh did I forget?
One other thing you can do is go poking around looking for any ungrounded metal pieces in the system, and add a ground bond cable for it - no voltage = no current flow = very little galvanic corrosion. Mostly, the car makers do that, but did they miss any?
One other thing you can do is go poking around looking for any ungrounded metal pieces in the system, and add a ground bond cable for it - no voltage = no current flow = very little galvanic corrosion. Mostly, the car makers do that, but did they miss any?
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One area that I'm curious about for those of us planning to keep our 80s for as long as we can is how non-conductive the coolant we are using really is. I keep mine very fresh but don't know if 50/50 premix that I'm using is 100% non-conductive or just 95% or something like that? I'm wondering if a slight conductivity is present and that over the span of decades some of these aluminum parts may start to show some erosion even if the coolant is kept fresh. Maybe someone on this thread knows just how conductive or non conductive fresh coolant is or I'll search online later.
To add to the general conversation and re-confirm that anodes do work when deployed in many cases:
On my old sailboat I would typically need to change the zinc anode once a year in saltwater. The anode was bolted around the prop shaft and the boat was very rarely connected to shore-power. Typically the old anode would be about 50% eroded and I could break it off by hand to remove. One year I used a lot of shore power including a lot of battery charging and the anode was completely gone except a few small chunks when I went to replace it. Both erosion processes involved electrical connections between the various boat metals, all of which were bonded together so that the anode protected all. Shore power connectivity to the common-grounded batteries via a charger dramatically accelerated the process. In freshwater I ran Magnesium anodes and they eroded noticeably as well.
Seeing what happens to boats that are left in the water without anodes for a while is pretty interesting. The non-copper metals in Bronze are leached out leaving a dark red, potentially brittle metal behind, etc. I certainly don't understand all of the different processes or semantics involved but I've seen some expensive props, shafts and other below-water components get trashed. I've also consistently seen large anode plates installed on various commercial boats made of steel, aluminum and in one interesting case a boat with a hull of steel and deck of aluminum welded together. That last boat was made in Australia and was doing well after years of continual saltwater service and regular anode replacement
Further, the anode in my campers hot water tank shows clear erosion when replaced as it sits with tapwater in it through most of the season. That reminds me, I need to check the house water heater!
To add to the general conversation and re-confirm that anodes do work when deployed in many cases:
On my old sailboat I would typically need to change the zinc anode once a year in saltwater. The anode was bolted around the prop shaft and the boat was very rarely connected to shore-power. Typically the old anode would be about 50% eroded and I could break it off by hand to remove. One year I used a lot of shore power including a lot of battery charging and the anode was completely gone except a few small chunks when I went to replace it. Both erosion processes involved electrical connections between the various boat metals, all of which were bonded together so that the anode protected all. Shore power connectivity to the common-grounded batteries via a charger dramatically accelerated the process. In freshwater I ran Magnesium anodes and they eroded noticeably as well.
Seeing what happens to boats that are left in the water without anodes for a while is pretty interesting. The non-copper metals in Bronze are leached out leaving a dark red, potentially brittle metal behind, etc. I certainly don't understand all of the different processes or semantics involved but I've seen some expensive props, shafts and other below-water components get trashed. I've also consistently seen large anode plates installed on various commercial boats made of steel, aluminum and in one interesting case a boat with a hull of steel and deck of aluminum welded together. That last boat was made in Australia and was doing well after years of continual saltwater service and regular anode replacement
Further, the anode in my campers hot water tank shows clear erosion when replaced as it sits with tapwater in it through most of the season. That reminds me, I need to check the house water heater!
I love the science here, and I really appreciate you scientist.
But tell me, at this stage in the game of 277,688 miles on my engine, would using a zinc anode do anything to save me from the dreaded corrosion? Is this an item that is best served on a fresh engine?
devo
But tell me, at this stage in the game of 277,688 miles on my engine, would using a zinc anode do anything to save me from the dreaded corrosion? Is this an item that is best served on a fresh engine?
devo
It's things like this that make me enjoy this forum. VWVortex (the ooollllddddd days) or R3Vlimited, are nothing more than a bunch of kids seeing how big of a burnout they can do and then bitching about how they grenaded something in the process. Thanks to all the brains here!
NLXTACY
Wits' End
- Thread starter
- #35
Ions don't get replaced. Whatever damage is done, is done. But this prevents any further corrosion. It really depends on the condition of your motor and how meticulous the servicing has been. On my SC LX I have zero concerns. But I've opened up a few trucks lately that make me wonder what the hell the PO was doing.
In a closed system, won't that zinc become deposited somewhere? Or do you expect it will stay in suspension?
gofast
SILVER Star
I'm in. Having aluminum body land rovers before I went to the dark side I had good success with sacrificial zinc. Aluminum just flakes away otherwise.... kinda of thought it needs air to oxidize but what do I know and cheap insurance. Count me in
Hi this is my first post on mud.
This is a very interesting post and I had a couple of questions.
Background: I have a work in progress restomod fj40 running a 5VZFE (Iron block with Al head) with the original (40 series) copper core radiator. Should I switch to an AL radiator to prevent the head from corroding or is the galvanic effect minimal because of the AlO3 forming? Also is there any other ways to introduce Zinc to the system, which do not require procuring parts that would be impossible for me to get in Pakistan?
Any answers/thoughts would be welcome.
This is a very interesting post and I had a couple of questions.
Background: I have a work in progress restomod fj40 running a 5VZFE (Iron block with Al head) with the original (40 series) copper core radiator. Should I switch to an AL radiator to prevent the head from corroding or is the galvanic effect minimal because of the AlO3 forming? Also is there any other ways to introduce Zinc to the system, which do not require procuring parts that would be impossible for me to get in Pakistan?
Any answers/thoughts would be welcome.
It's also a house thing. I just passed on buying a home in the county, it seems that when the current owner decided to "up date" her plumbing system she had someone who didn't know what the hell they were doing do the job. Her plumber, and i use that term lightly, mixed black pipe, copper, and galvanized together without the use of any connectors to prevent galvanic corrosion. What a total, and complete s*** show, and don't even get me started on the electrical in that home. Thank god for pre buy inspections, that inspection cost me 500 bucks, but it turned out to be the best 500 bucks i ever spent.
