I have replaced them many times and never had any significant amount of
oil leak out while doing so.  You might get a drop or two.  I usually
pull the old one and put the new one right back in so maybe if you let
it set for a day without anything in the hole you might get some
leakage, I don't know.  You should not run into any problems.

Ken Wilford
John 3:16
www.vanagain.com

Allan Streib wrote:
> I have a new sender on order, supposed to arrive tomorrow.  Will I
> need to drain the case to change this out, or is there only oil there
> when the pump is turning?
>
> Allan
> --
> 1991 Vanagon GL
>
>