of stuff used for insulation, just packed into a hot metal can under your car. Nothing crawled in. The muffler is coming apart on the inside and sending its own guts out the exit.
Why the Fiberglass Starts Coming Loose
Mufflers are welded assemblies, and the packing stays put as long as the internal structure holds. If internal components deteriorate or become damaged, the fiberglass packing may lose its support and begin working loose. Once there’s a path, exhaust flow drags more of it out over time.
Corrosion is a
