I have found (not on Vanagons, but on cars in general) that the
sender unit is far more likely to be faulty than the gauge in the
dash.  Usually there is a way to test the gauge by applying a
specific current to it - if it reads full with X volts, it is fine.
But the sender unit can get a small leak and not want to float
correctly.  Or the electronic of that same unit can be flaky.    Best
way to test thing is with a simple volt meter.  But I have not done
this on a Vanagon as I said, so someone with a Bentley manual can
probably help more with what to measure for.  I can tell you that for
a 1961 Ford Falcon (a car I long for still to this day, even though I
know it is not a VW) it was 3 volts you were after.

Good luck,
David.

On Jul 16, 2006, at 7:27 AM, karen d wrote:

> Filled up tank and gas gauge only shows about 3/4...any idea why?
> Do I need
> to replace something?
>