What was found
DURING CLIMBOUT, PASSENGERS REPORTED A FUEL LIKE SMELL IN CABIN. FLIGHT RETURNED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THAT APU WAS BLEEDING RESIDUAL OIL INTO AIR CONDITIONING SYSTEM, APU WAS CHANGED ON 10JUL96. REPLACED COALESCER BAGS, LEAK AND OPERATIONAL CHECK WAS NORMAL.