ive been doing some reading on this problem, and alot of people are saying that the anti freeze in the gm cars and trucks ''dexcool'' IS VERY BAD when it is mixed with air from a leaking manifold gasket like i have, it does a number of BAD things like turns to a brown sludge and plugs passages in our motors causing all sorts of problems like engine failure bearing wear when it is mixed with the oil in the block. hell there was even a lawsuit against GM and the prblems that this anti freeze has caused. what should i do about the anti freeze that is in my truck now???? flush it and replace it with what other brand since it calls for only the dexcool right? or am i wrong in this info what do you guys think??