As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER REPLACEMENT OF ENGINE OIL COOLER, OIL TEMPERATURE WOULD NOT RISE TO OPERATING TEMPERATURE. DISCOVERED REPLACEMENT COOLER WAS MANUFACTURED INCORRECTLY WITH AN INTERNAL BAFFLE LOCATED IN THE WRONG PASSAGE CAUSING THE OIL TO NOT BYPASS WHILE COLD.