Thanks for the replies.
You describe the way I thought it must work, but that means that while the Accusump is filling, the
oil level in the engine is dropping by 3 quarts until the Accusump is filled?!
There's no way to fill the Accusump separately, as you do the filters, other than by letting it draw down the main
oil supply for the engine. Intuitively, this sounds like a bad thing to do...run engine until it's 3 quarts low, then fill it up.
Thanks