As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A FOREST FIRE ACTION, THE PILOT NOTICED AN OIL LEAK COMING FROM THE TOP OF THE LT ENGINE. SHUT THE ENGINE DOWN AND RETURNED TO THE FIELD MAINTENANCE BASE WITH OUT INCIDENT. MAINTENANCE FOUND TWO CRACKED CYLINDERS. THEY CHANGED THE CYLINDERS AND GROUND CHECKED THE ENGINE AND FOUND IT TO BE SERVICEABLE.