Hairyplane, Not wishing to be alarmist but I'd be very interested in finding out the mode of failure to ensure that this problem does not reoccur. The failure of the oil cooler may be a symptom of problems elsewhere. Have the engine crankcase vent and the oil system pressure relief valve been checked. Oil coolers are fairly delicate items and if pressurised they split quite easily. However if the failure was caused by overfilling the engine with oil, or mechanical damage from foreign bodies, it would explain the subsequent behaviour.
Fly safely
WM