In my years of working on these things and Audis etc, I can only
remember seeing 1 bad trans cooler. The engine oil coolers do fail more
frequently, probably due to pressure surges in cold weather.

As for green coolant being more corrosive that blue, this is simply not
true. The major issue with standard coolant is the phosphates and
silicates coming out of solution when used with "hard" water. This is
the hard white deposits often seen at hose connections or in coolant
passages. The next issue is the abrasiveness of these phosphate-silicate
additives. Due to the thinner materials these abrasives wear through
radiators and heater cores. Abrasion is part of the corrosion control
solution.

The newer long life antifreezes use different chemistry and materials
for the scrubbing action. This is the redish orange deposits this stuff
leaves at leaky connections. I use these products.

All coolants, when heated and exposed to air become corrosive. The
corrosion on the heads that is often blamed on the wrong antifreeze is
really due to the gasket failing first. If the gasket didn't fail, the
antifreeze would not be there to cause the corrosion. I system that
requires regular make up water is also prone to internal corroision.
Everytime you add fresh water and coolant, you are also adding oxygen.
This oxygen will got to work until it is separated and either used or
expelled.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of jbange
Sent: Friday, December 03, 2004 12:15 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Replace trans oil cooler? 90 Vanagon automatic

At 10:55 AM 12/2/2004, you wrote:
>Should I heed the warnings out there, and have the transmission oil
cooler
>replaced before it breaks and causes mayhem? The ORIGINAL battery on
this
>van lasted a whopping 13 years. I don't expect all the parts to be so
>tough. Again this is a 1990 Automatic trans water-cooled Vanagon. I've
>read that this part should be replaced every 10 years. True?

I also have a 90 automatic. Of course the darn PO didn't have a single
scrap of documentation, so I've essentially had to assume that
EVERYTHING
is possibly original (except the engine-- 167000 miles, it's surely been
redone once). The one and only time I took it to the local VW
stealership
they pressure tested the cooling system. I too had heard about the
infamous
tranny cooler failure (from reading the GoWesty site) and managed to
actually speak to the VW mechanic about it. The idiot PO was running
corrosive green crap and tap water in the cooling system, so he said
it'll
PROBABLY be ok so long as I keep the coolant non-corrosive, but there is
(unfortunately) no way to know. The blue stuff will keep it from getting
any worse, but I don't think there's any way to tell if the damage has
already been done and the cooler is on the verge of losing it. I've just
been depending on my good fortune up till now, but I suspect that when I
get around to doing the head gaskets (stupid weeping things!) and have
the
coolant out already, I'll probably shell out the 250-odd dollars for a
new
cooler (owning a Vanagon is a vow of poverty, it seems...).

So I guess the answer to replacing the cooler is....maybe? The VW
mechanic
indicated the coolers fail because of corrosive coolant , so I guess it
all
comes down to gauging how much time it's spent with bad coolant in it
(and
they all came filled with bad coolant from the factory, as I've heard).
I
guess it comes down to how detailed a service history you have, and
whether
you believe a mechanic working at the dealership who's possibly trying
to
sell a new cooler.

Anyone else have any ideas on the matter?

John Bange
'90 Vanagon "Geldsauger"