As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) HIGH OIL TEMPERATURE AND BURNING ODOR IN CABIN PROMPTED RETURN TO AIRPORT. COMPRESSION CHECK REVEALED LOW COMPRESSION NR 3 CYLINDER, REMOVAL REVEALED A PORTION OF THE SECOND RING LAND APPROX. 1.5 INCHES LONG BROKEN OFF THE PISTON AT THE 10 O`CLOCK POSITION VEIWED FROM TOP.