As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING ENGINE REPAIR, CYLINDER SHROUD TUBES REMOVED. SHROUD TUBE O RINGS PREVIOUSLY INSTALLED WERE BLACK IN COLOUR. BOTH OEM AND PMA O RINGS FOR THIS MODEL OF ENGINE ARE ORANGE IN COLOUR. COMPARED TO THE OEM O RING, THE BLACK O RINGS ARE DIMENSIONALLY DIFFERENT. (TC# 20190717007)