Date:         Fri, 12 Apr 2002 11:11:11 -0700
Reply-To:     gary hradek <hradek@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         gary hradek <hradek@YAHOO.COM>
Subject:      Leaky electric heads on vanagons?   Stay grounded
Content-Type: text/plain; charset=us-ascii

Caught this article in our SJMercury News
Still another reason to check those ground.
         gary

http://www.bayarea.com/mld/mercurynews/classifieds/automotive/3049637.htm
I have a 1993 Chevy Lumina sedan. The heater core
started leaking in December 1997 and was replaced by
the dealer for $271. The leak returned in January 1999
and was replaced by the dealer at no charge. The leak
returned again in May 2001. The dealer stated there
was some foaming in the coolant and estimated $525
parts and $960 labor to repair it. They basically
wanted to replace all hoses, radiator, belts, etc.
This seemed like, ``We don't know what's the problem,
so let's replace everything and see what happens.'' I
refused and had just the core replaced on May 21,
2001, costing $460.

The leak has returned again. Do you have any
recommendation on how to determine the real problem
and solution?

Ron Taylor

A I hope others will be OK with me jumping this letter
to the top of the to-do list, as you have certainly
had a rough time with the Lumina's heater.

Corrosion and erosion within an aluminum heater core
or radiator can be a serious problem if the cooling
system isn't serviced regularly, or seemingly harmless
electrical faults are occurring. I checked with Pat
O'Conner of Buffalo, N.Y.-based Fedco Automotive
Components, a leading manufacturer of heater cores,
and learned that coolant acidity, contamination and
electrolysis can cause repeat heater core failures, in
some cases more frequently than yours.

Many repair shops and car owners simply renew a
leaking heater core without giving much thought to
coolant condition, as long as the color looks good. As
coolant ages, its protective qualities diminish,
allowing acidity to increase and abrasive particles to
form and circulate. When the coolant's PH level
changes excessively, aluminum components such as
radiators, heater cores, timing gear covers, and even
cylinder heads can fall victim to attack.

The radiator and heater core, with their thin walls,
are often the first to fail. Erosion of these same
parts also can occur as a result of coolant
contamination. Foundry casting sand, gasket material,
silicate drop-out and other debris can wear away the
walls of a heater core or radiator, especially if the
flow restricter has been inadvertently removed.

Electrolysis is the most likely cause of your Lumina's
repeat failures, as a poorly grounded electrical
accessory can cause current to flow through the
coolant. This causes aluminum parts to oxidize, and
can lead to rapid perforation of the radiator or
heater core.

While a typical iron/aluminum engine may see .1 volt
(measured by immersing a voltmeter probe in the
radiator neck, the other to ground with the engine and
all accessories functioning) due to galvanic action,
higher voltage (.3 volt or more) can cause serious
damage. GM service bulletin 73-62-13 and AC Delco
Tech-Connect volume 2, issue 6, both contain important
information on the effects of electrolysis and how to
rectify it.

Besides checking for and correcting an elevated
coolant voltage level, one of the most important
corrective steps is to thoroughly flush the cooling
system (or drain/refill/run/drain three times) and
fill with a 50 percent to 65 percent coolant/water
mixture. My hope is that your unfortunate situation
will inspire others (including myself) to service
their cooling systems more regularly.


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