As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5312 STL TO EWR - WHILE CLIMBING TO CRUISE ALTITUDE, A PASSENGER HAD NOTICED A STEADY STREAM OF FLUID TRAILING OFF OF THE RIGHT WING. AT THAT TIME THE FLIGHT ATTENDANT CONFIRMED THE STREAM AND NOTIFIED THE CREW OF THE SITUATION. THE FLIGHT CREW THEN RAN THEIR QRH AND DECIDED TO RETURN TO FIELD WITHOUT INCIDENT. MAINTENANCE ARRIVED AT THE AIRCRAFT AND FOUND THE RIGHT VENT VALVE LEAKING. MAINTENANCE REPLACED THE VENT VALVE AND CONDUCTED AN OPERATIONAL CHECK WITH NO DEFECTS NOTED.