What causes a muffler heat shield to wrinkle and warp to the point that it gets cut up in the belts and pulleys? The owner thinks this is due the effects of moisture from storing the car for so many years under a carport. He thinks it got wet and stayed wet for too long. I'm wondering if this could have been caused by the exhaust system from over-heating. The car has 19K miles on it and the owner says that the muffler has been replaced because it 'went bad'. He quit driving the car several months ago because it was 'flooding'. Based on this information, is it likely that the engine was running too rich and over-heated the muffler? And if this is the case, what can cause an engine to do this? A bad control pressure regulator? Also, what is the best replacement for this heat shield? Are the replacements available made of asbestos? Thanks, Walt Tampa, FL