What was found
PILOT REPORTED EXHAUST LEAKS. AIRCRAFT HAS LARGE EXHAUST STAINS ON THE COWLING AROUND THE EXHAUST STACK ACROSS THE BOTTOM OF THE AIRCRAFT AROUND THE LOUVERS ON THE LT SIDE OF THE ENGINE COWL, AND SPREADING BACK ACROSS THE LT SIDE OF THE ACFT ACROSS THE CABIN VENT AND UNDER THE WINDOW. EXAMINATION FOUND THE SLIP JOINTS BETWEEN THE EXHAUST RISERS, P/N 11-0864, AND THE MUFFLER ASSY, P/N 7-1553-2, WERE LEAKING. THE DESIGN AND MANUFACTURE OF THE PARTS DOES NOT LEND ITSELF TO A TIGHTER FIT. OPTIONS FOR SEALING THE LEAKS ARE BEING INVESTIGATED.