The type of coolant has nothing to do with water pump bearings failing.
If the coolant reaches the bearings, than the pump has failed anyway.
Coolant can effect the seal life since the seal is a friction device and
the coolant must lubricate it. We really have the same story with
Waterboxer head gaskets. The corroision does not cause the gaskets to
fail, but rather is the result of a gasket that has failed. Once the
coolant leaks past the gasket barrier, it mixes with air and dirt while
heated, creating a corrosive mixture. This then begins to eat the head
surface. Notice the corrroision usually ends inside the gasket area, it
only occurs under the rubber where the leak begins.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf
Of David Brodbeck
Sent: Sunday, March 02, 2003 2:53 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: What's wrong with my VW? Friday

>
>
>>I can't agree. Modern engines should be low-maintenance, and coolant
>>type uncritical.
>>
Not necessarily true in practice, though...many Honda owners have
reported that Hondas will chew up water pump bearings if you don't use
the special Honda coolant.  Very bad, since Honda water pumps are driven
off the timing belt!

Modern engines seem to be *more* coolant critical than older ones.  Most
of them won't tolerate the generic green Prestone stuff anymore.  The
formulations seem to be pretty specific for each manufacturer now.

>> VW is neither. Japanese engines will take abuse and
>>total lack of maintenance and still give really high milages (of
>>coures there ARE unreliable Japanese engines, but most are
>>bulletproof).
>>
>>
This is a myth from what I've seen.  Japanese engines are *very*
reliable but they won't tolerate neglect.  In particular, they have
short lives if oil changes are neglected.  If you want to neglect your
engine, buy a big dumb American V-8.  The loose tolerances and cast-iron
construction mean they'll take a lot of abuse.