"Today's newer aluminum engines create a problem for water-glass based sealers. Aaluminum expands and contracts about 33% more than steel. Water-glass brands cannot expand or contract because it's glass, so it simply cracks off. Todays newer vehicles require a liquid sealer that can flex and expand with the engines aluminum parts so as to not just crack-away. So far, the only brand I've found that doesn't use water-glass as a main ingredient is Dura-Seal..."