Date: Thu, 14 Oct 2010 08:48:24 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: [Syncro] Stainless Coolant Pipes Endanger Engines
In-Reply-To: <4cb70b86.6155e60a.65c7.ffffd6c0SMTPIN_ADDED@mx.google.com>
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Galvanic Corrosion is very real.
It may be one cause of why WBX motors have such head gasket problems..Just
guessing on that..
But Galvanic Corrosion can be remarkably destructive in a very short time
period, especially if some unforeseen circumstances occur to promote
accelerated electrolysis between dissimilar metals in a system. I worked
for a time in the boatyards, where we dealt with the results of galvanic
corrosion on a daily basis...seawater being a very good conductor. Boats
would sometimes sink because the metal fittings through the hull corroded
away and let the ocean in.
We had one repair job where a very expensive sailboat sunk in it's slip at
the marina. We'd maintained this boat as a regular customer, recently
hauling it out and replacing all the sacrificial anodes ("Zincs") checking
the rigging and doing a bottom job as well as our normal inspection for
saftey. About a week later, the yachtowner calls in a panic! "My boat
sunk!"...so we took our service launch to his marina and found that his
bronze thru-hull fittings had all turned to chalky green swiss cheese, when
just the week before, we'd gone over every one, checking them and found them
all to be in perfect shape. Well, further detective work turned up the
cause..The boat in the next slip...It's owner's shore power cord had slipped
overboard. The Marina's electrical system, for some reason, didn't blow a
breaker. So this fellow's boat's zinc's went first, shortly followed by the
bronze of the through-hull fittings and his Stainless rudder gudgeons and
the propeller, and the prop shaft, those were also trashed...not to mention
the whole boat's damage from immersion.
Stainless steel screws or fittings that contact an aluminum mast, those
are also very prone to corrosion..but less so because they aren't immersed
in a conductive medium full time.
I would think, if some wire got loose in the engine/cooling system of a
van with SS pipes..that kind of enhanced electrolysis *could* happen to some
degree. Not saying SS coolant pipes are a No No...but galvanic corrosion IS
a real issue where dissimilar metals might be connected by a conductive
medium (your coolant) and there is electricity around..
Modern yachts normally use non-metal through-hull fittings now and
stainless screws into aluminum masts, most good yacht workers coat the
screws in some kind of isolating compound so they don't "weld themselves"
together.
Reading some of the newer posts...Adding another metal to the mix already
in the VW...who knows? VW now uses SS? They may not be planning on their
current vehicles being around for 30yrs...There probably won't be any
gasoline left to run them then, anyhow.
Don Hanson
On Thu, Oct 14, 2010 at 6:51 AM, Derek Drew <derekdrew@derekmail.com> wrote:
>
>
> It has become very common in Vanagon circles for owners to change
> their coolant pipes to stainless steel designs.
>
> Terry K introduced one of the first stainless steel pipes in North
> America, and other thinner walled pipes were later introduced from
> Europe and elsewhere. Now, many vendors offer stainless pipes, and
> the plastic pipes that seemed so stupid to us because they fail are
> becoming NLA (no longer available).
>
> An argument came to my attention this week at RJES that the use of
> stainless steel for coolant pipes is a kind of an idiot thing to
> do..... a kind of automotive-engineering-101-no-no.
>
> Apparently, engine coolant tends to be conductive enough that even
> though the stainless pipes are not touching at either end, the
> stainless pipes can create a battery (galvanic corrosion) and cause
> the engine to start turning into a more dust like material over time.
>
>
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