Date:         Fri, 11 Jul 2003 09:17:08 -0700
Reply-To:     Harald Rust <harald_nancy_vw@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Harald Rust <harald_nancy_vw@YAHOO.COM>
Subject:      Re: 89' Wolfsy - Vanagon Syndrome
Content-Type: text/plain; charset=us-ascii

How to install 1 internal and 1 external micro
cooling fans on your Ecu:
The Ecu does get very hot, and it's a real problem.
The Ecu is virtually sealed and water-tight,
except for the tiny vent on the bottom.
So the heat stays in it.
I've added an external cooling fan, a small
(I think about 1.5" in dia.)
in the westy cabinet pointing to the cooling
fins of the Ecu.
It's easy to add in a westy. You just have
to cut a small hole on the right side of
the Ecu, as you look at it, under the bench
seat, and bolt the fan in place there.
It draws fresh air from the right,
not from where the heater core is.
How effective? It will cool the cooling fins
and all the components that are attached to
the heat sink inside the Ecu.
However,
the real heat problem is inside the Ecu on
the circuit board. There are several components
which get so hot that the circuit board
of most Ecus is damaged, and solder connections
get hairline cracks and corrosion.
When you remove the cover of the Ecu,
it's easily visible.
Darrell Boehler came up with the idea
to resolder the damaged solders and
had some descriptions on how to do it.
How to prevent this heat damage on the
Ecu circuit board from recurring?
I doubt an external fan will make enough
difference.
So here's what I did:
(I've been driving with this extra fan
for a year now.)
I bought the smallest micro muffin fan I could find,
about 5/8-3/4" across or so.
Cut a hole the same size as the micro fan in
the Ecu cover, on the flat area where the
Bosch part number sticker is, towards the end
where the heat sink is. That's where the
circuit board gets hot.
It blows air straight down into the innards
of the Ecu. Now cut another hole on
the flat area towards the connector plug,
about an inch away from the end.
This is so the micro fan can pull in air,
after the aluminum cover has been installed.
Then you have to fabricate a small airtight
cover. I used sheet aluminum, and made
a cover about 4.5" long by 1.75" wide
by 3/8" or less high.
Then I used epoxy to secure the muffin
fan in its opening by the heat sink.
Also used expoxy to glue the aluminum
air flow cover in place.
All nice and airtight.
So now there's internal air circulation
inside the Ecu.
A year later, the circuit board solders
are still in good shape, and it totally
stopped all intermittent syndrome.
I hooked up both muffin fans, external
and internal, with a wire I ran to the coil.
Ignition goes on, fans go on.
(Disclaimer: Follow at your own risk.)
I also use the cap fix on my afm.
The cap fix does help, but the ecu was still
getting very hot, and causing some bucking,
especially on long trips when it's going all day.
Now with the cap fix, resoldering the Ecu
(according to Darrell Boehler),
installing 2 micro fans on the Ecu,
the bucking or intermittent symptoms have been
totally gone for a year. (knock on wood)
Harald
'90 westy
go here if you like to chat about camping:
http://autos.groups.yahoo.com/group/vw-camping/


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