What was found
AT THE GATE, THE FLGHT CREW REPORTED A VERY STRONG OIL ODOR THROUGHOUT THE ACFT WITH THE APU BLEED ON, ACFT WAS ON THE GROUND WITH NO EXTERNAL AIR, AND ENGINES SHUTDOWN. THE ODOR DISSIPATED SOME WHEN THEY TURNED THE APU BLEED OFF. MAINTENANCE SUSPECTS THE APU TO BE THE SOURCE OF THE ODOR. AIRCRAFT WAS GROUNDED. MAINTENANCE INSPECTED APU COMPARTMENT FOR CONTAMINATION & LEAKS, NONE FOUND, OIL LEVEL GOOD. ACCOMPLISHED SATISFACTORY OPERATIONAL CHECK.