Hey gang, noticed the paint discoloring on the left side of my cowling over the last few weeks. Looked over the exhaust myself, but didn't see anything unusual. My A&P looked her over today, and pointed out the crack around the muffler tube junction that I could only see with a real bright flashlight. In going over my logs, this exhaust had a crack and was welded at 180 hours, and then replaced it at with a new muffler at 240, it now has 410 and is cracked again! Sorry, but this is not an acceptable situation to me. Has anyone any experience with A. what causes this, and can the cause be removed? B. if not, is there a better exhaust out there, LEES, or something else that does not crack?