Be very careful in handling the heat shield. It is made of asbestoes and should be treated with care. Do not breath in the fibers and try to minimize creating any. It sounds like the mixture is very rich, see if the muffler is glowing red. To adjust you remove the tamper plug on the mixture unit and adjust the setscrew in the mixture unit. You really need an emission analyzer and exhaust port set-up to do it right, a minor adjustment has a large effect. To replace the shield most Delorean venders have a non-asbestoes shield which looks just like the origional. Be sure to dispose of the old one properly it is asbestoes and there are strict rules regarding it. I replaced mine and for a while the new one emitted a terrible odor until it finally was gone. Mechanically it is pretty easy to replace but I would first adjust the fuel system so as not to burn up the new shield. David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxx, "Walter" <Whalt@xxxx> wrote: > 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