No. At least that was what was told to us this weekend at the bd workshop. The soap and water are kind of in suspension until it reaches a really warm place like the engine. Then it's immediately out of suspension and it warms and explodes causing pitting in the cumbustion chamber. Can also happen inside the IP causing pitting there. Soap can also cause incomplete combustion and coking of the injectors and carbon build up on the chamber walls wihich may cause siezing.
I'm with you. I don't want to wash it either. On newer engines though you must. I think you can get away with it a little maybe with incomplete washing in older MBs.
Drying is really important, too. I've been using a bit of heat (propane) to separate the water then pouring off the bio leaving the water at the bottom of the container.

One other thing to try is getting all the methanol out of the unwashed bio before you begin washing. By evap or by heat. The methanol will hold the water and soap in the bio. Without it the crap falls to the bottom in about 10 days, or so I've been told. Then use just the top and you're better that if you just made and poured into the tank. But not at good as several washings.
If you use virgin oil there is almost not soap to begin with, no FFAs from heating so the soap is so small that when I washed a virgin oil batch the first wash water was almost clear.

If you can, try doing a glycerin prewash. After the agitation is complete, add water at about 5% of the amount of oil. This will help get the extra glycerin out, won't make the water go into suspension so it will fall out the bottom. It will get some of the soap out and all you'll need to do it drain off the water and glycerin and the first wash will be done.

Good luck in whatever you decide.
I don't want to wash either. Waste of water.
BUT, there is a chance that I'll begin using the 2-4 wash waste water for watering my yard this year. The yard will love the soap. I'll have to switch to potasium hydroxide to do that though.


There are many who don't wash, but they are also driving older diesels that have had the crap fuel for 20+ years.