What was found
AIRCRAFT WAS GROUNDED: ON CLIMB OUT, FLIGHT ATTENDANT CALLED THE FLIGHT DECK AND REPORTED THAT SEVERAL PASSENGERS WERE REPORTING FUMES AND A MUSTY ODOR IN THE CABIN. AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO CLT WHERE IT LANDED SAFELY WITHOUT FURTHER INCIDENT. **ORIGINAL REPORT WAS AALA20220406867** MAINTENANCE FOUND OILS LEAKS AT THE APU OIL COOLING FAN AND THE APU OIL COOLER. MAINTENANCE REPLACED THE APU COOLING FAN AND THE APU OIL COOLER (AALA202204074072), A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ODORS BEING NOTED.