I've been doing the solvent flush for over 50 years, and the only engines I've experienced problems with already had internal damage that the thinned-out oil could not have created. One that's knocking already from a damaged bearing or a scored crankshaft won't get magically healed by a little Diesel fuel, but it's by far the best way to clean out a sludged-up crankcase. By overfilling the oil pan, the crankshaft whips down into the liquid like the agitator in a washing machine and splashes the oil/Diesel mix in all directions. Drain the pan while the oil is still hot and most, if not all of the sludge comes out. There's no way to do a better job of cleaning with a brush and solvent with the pan off.
Jerry
