As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) INSTRUCTOR RETURNED FROM A FLIGHT WHERE HE EXPERIENCED A ROUGH ENGINE AND LOSS OF POWER FOR A FEW MOMENTS, AFTER WHICH THE ENGINE RAN NORMALLY AGAIN. WHEN MAINTENANCE REMOVED THE COWLING TO CHECK OVER THE ENGINE, A LOT OF OIL WAS NOTICED IN THE COWL, FURTHER INSPECTION AND CLEANING FOUND A 2 INCH LONG CRACK IN THE CRANKCASE FROM CYLINDER NR 2 MOUNTING PAD AND FORWARD. (TC NR 20070625001)