As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING LATEST INSPECTION IT WAS REQUIRED TO OPEN UP THE LOWER WING ROOT PANELS. WHEN LOWERED I NOTICED A SMALL AMOUNT OF FUEL ON THE TOP SIDE OF THE PANEL. THE LEAK WAS FOUND TO BE THE LH AFT FUEL SELECTOR VALVE. I PEELED AWAY THE PRO SEALANT AND SPLIT THE VALVE TO FIND WHERE A SMALL O-RING SHOULD BE THERE WAS NONE BUT RATHER WAS FILLED WITH PRC INSTEAD (AIPC 28-23-01 FIG 1 ITEM 19.