We had a driver put about 1 gallon def into fuel. Truck stayed running but not well. I discovered the issue by finding the crystals built up in the water drain. I immediately changed filter set . Then filled from 1/4 tank to full. Ran a little then changed filters again. Also drained bowl 4-5 times. I then cleaned filter housing and installed third set w plent of diesel kleen and the truck hasn't skipped a beat yet. That was 15k miles ago. These are tow trucks and are used heavily. With something like this time is imperative and a little luck never hurts
L1 master, I-car certified collision, paint