I have a '96 GMC with a 6.5L turbodiesel. I'm currently running WMO through it in small quantities and I haven't noticed anything yet. I'm at about 10% right now. It was my intention that this would help the IP live longer with today's Ultra Low Sulfer diesel, but it's also saving me 10% fuel cost, which is nice...
My deuce is running more like 25% WMO right now, but it doesn't go far.
I don't use WMO from diesel engines if I can help it because the soot really thickens it and I can't see how that would be good for the fuel system. I'm filtering through a paper paint filter-funnel on the way into the tank. (Oh the horror of it!!) I'm going to set up a filter bag system and "clean" barrel for storage soon. This way I won't have 20 1gal jugs waiting to get used.
C