Well, more out of curiosity than anything else, I decided to go ahead today and change the oil in the HPOP reservoir in my Excursion 7.3 while doing an overall engine oil change. The long hood on the Ex made it much easier than doing this on a van.
Worst part was using a large syringe to evacuate the reservoir. It took a long
time. I did take Tom's experience as a warning, and did this to my syringe tubing (just in case) so there was no way it could drop into the reservoir.
I am not going to do multiple changes in hopes of completely cycling the HPOP reservoir oil. I'm not that interested. I did substitute a quart of Archoil AR9100 for one quart of Motorcraft 15W-40 but I have not started it yet because I'm waiting for the oil level to settle. There's a chance I overfilled by a quart, so I may have some draining to do (good thing I have a Fumoto valve.).
I don't know if this oil filter wrench would work on a van, but it is by FAR the best oil filter wrench I have ever used. I've never had a hard time removing an oil filter with this thing (you use your ratchet with it). Unfortunately, between my other vehicle's smaller diamter oil filters, or just a lack of room, I can't use this wrench on any of my other vehicles.