chem test

I'm not a chem major, but researched this in about 10 minutes...Google is my friend.

Zinc sacrificial anodes can be used to prevent corrosion in aluminum; zinc is a more active anode than aluminum and will corrode first.

Your home's steel water heater uses an aluminum or magnesium anode, same principle.

Is it worth 20 bucks? Thats up to you.

--Don Don Byrer KJ5KB Power & Glider Pilot Guy kj5kb-at-hotmail.com

"I have slipped the surly bonds of earth; now if I can just land without bending the gear..." "Watch out for those doves..."

Hmmm... you just destroyed your car's engine and radiator.

ok, i believe you may have found someone saying that - as does what i cited, but i have to ask, where did you find your source for that statement?

indeed, either will protect a steel heater tank. but zinc will not protect aluminum because...

electrode potentials: Fe, -0.44V Zn, -0.76V Al, -1.66V Mg, -2.36V

thus zinc [and aluminum and magnesium] will protect steel, but steel will not protect anything on that list because of its lower voltage. and similarly, zinc, with its lower potential, will not protect aluminum and aluminum will not protect magnesium.

of course not - it won't work. not only is the potential wrong, there is no direct contiguous connection between components like a radiator and a cylinder head, thus, just like a sacrificial anode will not provide cathodic protection to a ship hull above the waterline because there is no electrical circuit, putting a zinc anode into a radiator hoping it will protect an aluminum head will not only not protect the aluminum because of insufficient potential, it doesn't even have a circuit either.

fact is, the best protection for aluminum vehicle componentry is the correct formulation of antifreeze, and use of distilled water as dilutant. end of story.

this stuff is amazing to me. i can understand people not knowing and not knowing what to look for, fine. but making stuff up, not asking someone who actually /does/ know, and getting it wrong, and then going out and trying to sell stuff based in incorrect information, just makes my brain hurt.

don't we teach /anything/ in schools any more?

bending the gear..."

With the presence of so many other less electrochemically active metals in the system, not to mention the effects of passivation and the fact that the composition of the heads is hardly elemental aluminum (which itself develops an oxide film rendering it relatively corrosion resistant, albeit some- what inefficiently in a hot coolant enviornment), the elemental zinc will, at worst, do nothing at all. Additionally, anyone harboring the ficticious, concocted belief that no electrical connection exists between the engine and radiator (were that the case, corrosion in an aluminum and plastic raditor would be of concern solely regarding pH extremes), is invited to competently deploy a VOM to dispel that presumed myth.

Right. One problem with water heaters in a home is when different metals like copper (flex hose) and steel (tank) touch each other. That can cause a small electric current to occur - sort of like making electricity from an orange in high school science class.

And to prevent this, they use a "dielectric union" which does not conduct electricity.

And in a car they use non-electrically conducting radiator hoses! And rubber mounts for the radiator.

Anyway is this a problem with cars with aluminum radiators?

In the past I have had copper radiators which I replaced because they were clogged due to many years of use - not leaking. But have not owned a car with an aluminum radiator for a long period of time (yet).

Here is an interesting discussion of this...

To learn more, search google.com for the following words...

electrolysis

cathodic protection

dielectric union

hull zink

orange electricity

that's not why those hoses and mounts are used - it's to protect the radiator from vibration and fatigue and the body flexes. and of course, rubber hoses allow the engine to move on its mounts.

not if you use a good quality antifreeze and only dilute it with distilled water.

aluminum radiators are good because they /don't/ use solder in construction. not only does this mean there are no differential metal potentials between its components, they also allow hoat antifreeze to be used - hoat is a good formulation that doesn't rely on silicates [and thus gives longer pump life], but it doesn't play well with solder.

all that's going to do is stumble you into what apparently is a gigantic quagmire of spectacular ignorance and outstanding misinformation.

back in the day of expensive voltmeters, people didn't probe stuff and so would leave it up to people who knew what they were doing in this field. today, with cheap easily available meters, any idiot can "measure" all kinds of stuff and make up stories to "explain" what they think they see. then they post it all over teh interwebs where it gets picked up and further distorted, just like a pack of kids playing "telephone".

hey, weisenheimer, why don't you get your beak out of that thesaurus and stick it into some research of common casting alloys, and their composition? then compare those constituents' electrode potentials to those of zinc.

if you spent less time with your beak in a thesaurus and more under the hood of other people's cars, you'd soon learn that the average radiator is rubber mounted and connected with rubber hose. if you think that provides a current return, then i think that's another avenue of basic learning into which you need to stick that proboscis of yours.

you will further learn under the hood of those cars that the average driver will fill their radiator with any old crap. and that any old crap provides the precise cocktail necessary to start corrosion.

as for bleating about pH, you clearly haven't ever been bothered to look up what modern antifreezes are made with. "hoat" stand for "hybrid organic ACID technology". it's used because it causes a type of corrosion whose product passivates the target metal surfaces. so go ahead and bleat all you want, but it's completely pointless if you don't understand what you're looking at, much less talking about.

he said, blithely waving his hands in circles as he fires up the manure spreader and drives it straight down the middle of high street.

Wrong. Among the common reasons are that some rubber mounts house collars or internal metal bushings that limit crush and provide electrical pathways as do some metallic transmission cooler lines. But don't necessarily take my word, or anyone else's, for that matter when you can so (possibly) easily confirm it for yourself. Please so inform should you require assistance in executing that simple, basic task.

Both electrolysis and pH imbalanced induced corrosion can result from a badly maintained coolant system, and don't even get me started on ebullient cooling systems and the nightmare of maintaining them.

really? so what would be the pH when it's "imbalanced"? quit this vague hand waving and quote some numbers.

actually, you're deliberately muddying the condensate by so mentioning. but of course, you knew that - it's why you did it.