As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE LOWER RIGHT ENGINE ISOLATION MOUNT IS BECOMING RUPTURED DUE TO CHAFING CAUSED BY THE PROTRUSION OF THE OIL SUMP PAN GASKET. THIS GASKET, WHEN DRIED OUT DUE TO HEAT, SEEMS TO ACT LIKE A KNIFE AGAINST THE ISOLATION MOUNT. TRIMMING THE GASKET STOPS THIS. SUBMITTER STATED THIS IS 3RD OCCURRENCE ON 3 DIFFERENT AIRCRAFT. (X)