As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU HAD BEEN RUNNING ON THE GROUND FOR APPROXIMATELY ONE HOUR AND SHUT ITSELF DOWN DUE TO HIGH OIL TEMP AS INDICATED BY (BYTE) LIGHT. VISUAL INSPECTION SHOWED THAT BLEED AIR ELBOW HAD BROKEN OFF OF EXHAUST STACK CLAMP AT THE WELD. RECOMMEND REGULAR VISUAL INSPECTIONS FOR CRACKS ON THE STRAP THAT HOLDS THE TUBE TO THE CLAMP. IN ADDITION, METHOD OF ATTACHMENT OF TUBE TO THE CLAMP BE MODIFIED TO REDUCE SHARP CORNERS WHERE CRACKS ORIGINATE.