Is it possible that the heat shield warped so badly because it got wet? Are these things susceptible to water damage? How much mileage should one expect to get from an OEM heat shield before it eventually wears out from normal use? You all have given some great advice so far. Thanks. The new ceramic heat shield sounds like a great product. I was wondering if a piece of sheet metal would work as good, but I suppose not. Walt Tampa, FL >What causes a muffler heat shield to wrinkle and warp to the point that it >gets cut up in the belts and pulleys?