As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, THE CREW RECEIVED A LEFT HAND OIL PRESSURE HIGH INDICATION AND RETURNED TO PIT. MAINTENANCE INSPECTED AND REMOVED A SHIM FROM THE LEFT HAND OIL PRESSURE REGULATOR IN ACCORDANCE WITH DOENIER MAINTENANCE MANUAL 79-00-00. OPERATIONAL CHECKS WERE PERFORMED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.