A319
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
Upon arriving at the gate in ZZZZ; the APU was started; bleed on with packs operating.  The flight crew conducted a walkaround.  As we climbed up the jet bridge; we were greeted by the flight attendants and the Station Manager advising us that the aircraft had a terrible odor; similar to smelly socks; burning crayons; and musty. A logbook writeup was made and the local maintenance started working on the writeup. After several hours they came up with the source being the number 1 air conditioning pack.  The next day we departed with Pack 1 on MEL. Sometimes you come across an aircraft that exhibits the distinct low odor of being 'old'. We must determine if this odor is embedded in the interior? Or is it slowly seeping through the vent system? I am aware our airline is at the forefront of addressing these odor issues and I understand they are in the preliminary stage of replacing the APU on the A320 fleet. [Captain recommends Company] should consider a safety campaign educating fight crews on the cause and types of odor events associated with air conditioning packs and APU.  I know several publications have addressed this issue in the past; but it keeps happening.
A319 Captain reported a fume event during pre-flight resulting in flight cancellation for maintenance action.