[DeTomaso] Sacrificial Zinc anode

Mon Jan 27 19:57:49 EST 2014

Galvanic corrosion is not magic, and it exists. Try this on your DeTomaso (or Toyota, for that matter): with a GOOD VOM set on the lowest possible milliamp scale, ground one lead and insert the other in the surge-tank opening so the needle is underwater and not touching any metal. If the reading you get is above 75 milliamps- of unpowered electrical current flow within your cooling system- you will benefit from a sacrificial anode. A reading below 50 milliamps probably will not benefit. Corvette owners who have run aluminum radiators and aluminum heads since the late '60s well know this phenomenon, and Corvette shops sell a lot of such anodes. Zinc is OK but magnesium is better (and more expensive). This home VOM-test above came from one of the largest Corvette specialty shops in the U.S.

Some areas of the country have such corrosive water, Fluidyne and other alloy rad makers have seen brand new radiators fail within a year from internal corrosion, even with fresh 50% anti-freeze inside (or so they're told during warranty returns). That's why, at some expense to the manufacturers, they now include a free bottle of concentrated anti-corrosion chemicals with each alloy radiator. It is usually but not always good for a year before it needs to be drained and replenished. 'Pure' distilled water is not recommended either- that stuff is 'activated' and is almost as bad as Coca-Cola at dissolving aluminum. De-ionized water is best. Check your local water sometime with a scrap piece of aluminum. Bubbles indicate the scrap is dissolving and it happens faster with higher temps- like in a running engine @200F. 

A second check: while the VOM is connected to your cooling system and you are getting a reading, turn on your headlights. Did the reading jump? If so, something in that circuit of your electrical system is poorly grounded, By progressively unplugging one thing after another on the specific circuit, it can be located. Bad electrical grounds or 'ground loops' can apparently join with galvanic corrosion to make things worse.

Note- this test depends entirely on using a sensitive VOM; a $9 cheapo-meter from Radio Shack will not work because it's too insensitive to read milli-amps of current flow. The best you'll get is a flicker of needle movement. If you don't own a sensitive VOM, borrow one for a minute- that's all such a check takes. Our Pantera in northern CA showed 48 milliamps of current flow, and I found bad grounds on tail lights and side marker lights. When we moved to northern Nevada, the test showed 38 milliamps- better water I guess. Certainly tastes better....

-----Original Message-----
From: Clark Family <cclark at ix.netcom.com>
Cc: detomaso <detomaso at poca.com>
Sent: Mon, Jan 27, 2014 11:58 am
Subject: Re: [DeTomaso] Sacrificial Zinc anode

I would be very interested to see a picture or a careful weighing of a
sacrificial anode used in a car cooling system after 50k miles. For
marine applications, absolutely! But modern coolant has anti-corrosive
additives because of aluminum, brass, and iron in the coolant path.

Has anyone seen galvanic corrosion damage in a car cooling system? I
have read wankels had some that was solved by a simple ground wire.
Silica additives and not changing on recommended interval worries me more.

That Fluidyne suggests a sacrificial plug moves the needle a bit away
from snake oil. A quick search shows places selling 'voltage sponges'
and 'smart ground wires' along with anode radiator caps, really??

And it may hurt. What happens to all those active zinc or magnesium ions
put in solution? Do they precipitate and clog radiator tubes? Do they
plate on some other part of the engine? Does zinc stay in solution and
make waste coolant even worse toxic waste?

Monday musings,
Chris

On 1/26/2014 11:22 PM, jgkrenton at comcast.net wrote:
> All:
> 
> These are known as "Pencil Anodes" and are widely available in the
> marine industry.  Not a bad idea for any cooling system..
> 
> http://www.marinepartssource.com/products.asp?cat=7&CatName=Anodes&Sub1=3&Sub2=0&Sub3=0&SubCategory=Pencil%20Anodes
> 
> FYI
> 
> Jeff/2467
> 
> ------------------------------------------------------------------------
> 
> *From: *"Asa Jay Laughton" <asajay at asajay.com>
> *To: *detomaso at poca.com
> *Sent: *Sunday, January 26, 2014 2:01:53 PM
> *Subject: *[DeTomaso] Sacrificial Zinc anode
> 
> I'd recommend the zinc anode.  I first installed one in the water pump
> but later moved it to the upper hole in the Fluidyne radiator.  It
> doubles as an air bleed by opening it slightly, and doesn't cause a mess
> when I go to drain the radiator through the regular drain cock:
> 
> Flex-a-lite 32060 - Flex-a-lite Zinc Anode Drain Plug Replacement Kit
> 
> The photo is from Jegs because Summit doesn't have a photo. (and neither
> does the Fluidyne site).
> 
> Asa  jay

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