As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ROWS 14 TO BACK GALLEY THERE WAS AN ODOR OF ENGINE OIL FUMES COMING INTO CABIN. APU COOLING FAN WAS BLOWING OILY MIST, REMOVED COOLING FAN AND FOUND LARGE HOLE IN AFT RIGHT SIDE OF PLENUM. THE AIRCRAFT WAS GROUNDED. MAINTENANCE REPLACED THE APU IAW 26L31049005 AND PERFORMED SATISFACTORY OPERATIONAL CHECK.