Date:         Fri, 22 Oct 1999 16:27:40 -0700
Reply-To:     "T.P. Stephens" <doktortim@ROCKISLAND.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "T.P. Stephens" <doktortim@ROCKISLAND.COM>
Subject:      DM, Wasserboxer Cooling System
Content-Type: text/plain; charset="us-ascii"

>At 02:48 PM 10/22/99 -0400, you wrote:
> at the moment to my concern
>about flushing the cooling system and replacing the antifreeze.  Have
>you provided or recommended a procedure that I can use for this
>purpose?

Bentley outlines the procedure. You want an enhanced procedure??
Read on.

You must have a competant Jack and Jack Stands, not optional. Chinese
is risky. Disconnect the battery. Follow the Bentley procedure to fully
drain the system. Then raise the back of the van till the expansion tank
is higher than the bleed screw on the radiator. Fill with water to dilute the
residue until it flows out the bleeder on the radiator and drain again.

Now the procedure from Mercedes to clean and nutralise the scale.
Call the Mercedes dealer to find out about their chemicals (citric
acid and neutralizer). Buy that or experiment with oranges and
baking soda if you can accept the risk of failure. Fill the system
with the citric acid and water solution mixed per specification.
Realize you have twice the capacity of a Mercedes so you may need
twice the quantity  of chemicals they normally use.

Let it sit a coupla hours. Drain. Fill and drain with water. Fill with
the water/neutralizer mix. Let it sit for an hour. Drain. Fill and drain
twice with water for a final rinse.

Every time you drain you must lower the rear. Every time you fill you must
raise it again. Now raise the back for the last time and fill with the
premixed anti-freeze (non-phos e-glycol) till all the air and bubbles
are ejected from the bleed screw.

Every drain requires the head plugs be pulled and put back in to refill.

Then follow Bently procedure to do the final filling and bleeding.
Run the motor till hot and adjust the reservoir level in the morning
when cold. Be assured there will be little or no corrosive progression
for the next year at least. How much longer???? Not much. Once the
coolant turns south on you the curve to high electrolysis is quite
rapid.

After that, once a year just drain fully and refill. Always monitor
the reservoir level and note your rate of use. Anything over
a pint or so a month/5000mi is cause to start looking for the first
evidence of weepage.

Too much work for you?? You only have to do it this way if you expect
to actually have an impact on the problem, i.e., GET RESULTS.

Caution: if the vehicle is already showing excessive replacement rates
for coolant, the foundation of the leaking problem has progessed to
the point that this process can clean internal scale and start the
leaks to flow.

Want to improve the procedure?? Remove the radiator pipes and hoses
and clean them independantly. It just might be faster if you don't
have a hoist.

Keep the motor clean. Keep the battery clean. Problems here will lead
to a high propensity for electrolysis, i.e. ionic transfer of metals into
oxides. The killer is when this condition exists with anti-freeze that
has lost it's anti-acid buffers and the whole cooling sytem becomes a battery
with your motor, pipes and radiator as plates and the coolant the acid.
That's where the scale comes from, not at all dissimilar from the scale
that shorts out plates in an old battery.

Under the actual maintenance that most Wasserboxers get, 125k is the
neighborhood of first failures.


Doktor Tim
Maintenance Repair and Restoration of European Vehicles
San Juan Island, WA