As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DISPATCH MECHANIC NOTED SMOKE COMING FROM APU IN THE RT WHEEL WELL AREA AROUND EXHAUST DUCT. SUPPLEMENTAL DATA UPDATE, THE CAUSE OF THE SMOKE WAS BELIEVED TO BE RESIDUAL GLYCOL. HOWEVER, THE SEALS ON THE OIL BREATHER FITTING HAD WORN AND OIL WAS LEAKING EXTERNALLY INTO THE EXHAUST. THE AIRPLANE WAS ROUTED FOR APU REPLACEMENT.