Well I don't know about testing but since I've had to do things to the van
EVERY year that involved losing a bunch of coolant and refilling and burping
the damn thing I'd say most of us change the coolant more than once a year.

JMHO, YMMV, etc.

Mike

On 6/29/06 7:37 PM, "Alistair Bell" <albell@UVIC.CA> wrote:

> Of course the coolant is a conductor, but just as you can't light a
> light bulb with one copper wire going to it, to cant have
> electrolysis without a return path.
>
>
> Now before David B. chimes in with stray current problems in marinas,
> I understand their can be funny things going on with electrolytes,
> dissimilar metals, relative sizes of dissimilar metals etc. Indeed
> there are probably all kinds of cool electrolytic things going on in
> the stock set up.
>
>
> but in the car, one seemingly can isolate metal components "on the
> return path". And yes, there are dissimilar metals in the stock
> vanagon set up, metals of differing "nobility" and of differing
> surface area (exposed to coolant).
>
> Think of the brass in radiators, think of the cast iron, brass in
> sensors, aluminium in heads. I'd say that refreshing the coolant once
> a year would do much to quench runaway corrosion as any worrying
> about "isolated" copper in the system. i could be proved wrong of
> course :)
>
> Anyhoo, how many of us actually test our coolant , not for glycol
> conc, but for pH (which is an indication of corrosion inhibitor
> levels), and how many of us DO change and flush coolant every year?
>
> Alistair
>
>
>
>
>
> On 29-Jun-06, at 6:54 PM, Jake de Villiers wrote:
>
> Well, don't argue with me, I'm not a professor! The guy who laid it
> out on the Subaruvanagon list made a convincing case for the coolant
> being an electrical conduit. Electrons are pulled from the aluminium
> by the copper through the coolant.
>
> I'm pretty sure  the low coolant level sensor uses the water as a
> conductor.
>
> On 6/29/06, Alistair Bell <albell@uvic.ca > wrote:
> Jake,
>
> in circuits and electrolysis one needs a return path.
>
> isolate dissimilar metals with non conductor, its not a new idea.
>
> Alistair
>
>