Posted this before. This is how I drain my cooler. Have to think ahead.
Update:
Mine is a 9 row oil cooler from Pacific Cooler. Maybe I could have mounted it so the main lines attached on the bottom. But that would necessitate removing a line to drain the oil in it. Not something I wanted to do. This way the main lines are shorter at the top and the drain plug has worked very well for 18+ oil changes. There’s nearly a quart of dirty oil in there after draining the sump. I want as much out as easily possible. This is EZ.
This is not the case for me, I am going back to straight mineral and don't want to mix that with the existing oil that is in the cooler which is ashless dispersant oil.
I will remove the cooler which is only four bolts.