If memory serves, the '83 diesel uses the same "level tank" as the
waterboxer vans.  There should be two holes just below the license
plate opening, on the left side, that the mounting screws go through. 
Someone with an ETKA CD should be able to verify the part numbers.  I
have run with and without the level tank on '82 and '83 diesels and
found no difference in cooling system performance.  It seems to be
more of a convenience feature, allowing you to check and fill the
coolant without unloading the back of the van and removing the engine
lid.  Because of their design, they are not an absolute indicator of
coolant level.  Any leaks in the hose or connections negate the value
of the level tank as an indicator of overall coolant level.  If there
is a leak in the hose, you can lose all of your coolant and still have
a full level tank behind the license plate.

Michael Snow

On Fri, 4 Feb 2005 08:45:36 -0800, Dave Chameides
<docproteus@earthlink.net> wrote:
> After much monkeying around on my engine, I finally realized that while I
> have an expansion tank that has a filler cap, I have never seen a level tank
> (min/max markings).  I checked my owners manual and sure enough it says that
> the level tank is located behind the license plate next to the dipstick.
> Problem is, I don�t have one.  Any thoughts?  Were some years made without
> these?
> 
> Dave
> 
> 83 1.6 diesel
>