Brian, just to clarify. The section of pipe (~30mm long) welded to the muffler does not appear to be cracked at the weld. The exhaust pipe, which has a smaller OD, is inserted into the pipe section on the muffler. From the maint. manual no gasket is used to seal the join. The exhaust gas leak appears to be from between the exhaust pipe / muffler join. It'll be 10 days before I can get to the a/c to check the weld again. Regards, Bill