RT, this is where we differ. The oil can only move if there is pressure behind it or if there is a downhill run ahead of it. My statement is that there is NO PRESSURE on this oil, after it has made its pass through the filter. It would go nowhere unless there is a downhill run to the pan. Since there is an uphill loop, immediately after the filter, the oil will pool. The height of the pool will be from the top of the loop to the bottom of the filter.

You can do the same thing with your garden hose. Just run the water at a trickle, set up a restriction in the line, representing the filter, so that there is pressure ahead of the restriction, and then loop the hose on the downstream side of the restriction. The hose will fill completely with water for the entire lower end of the loop, because there is no pressure to move it along. Gravity cannot work uphill.

But, enough of this discussion. William has the right idea. The filter will probably do a fine job, even if it does run with an uphill loop. Personally, I'd like to install it without the loop because I am very confident that there will be oil pooling in the filter.