My EZ was in for it's condition inspection and we found two cracks in the engine mount, actually the tube on one wasn't just cracked but broken. Both were hard to see, obscured by baffling. My EZ has 1400 TTSN and is babied by me, no aerobatics and has a Lycoming 0-320. Luckily, my CI is being done by the Robert & Valerie Harris (EZ Jet fame) and they're repairing the mount to better than new condition.
What may have caused this?
I pride myself on closely inspecting the engine during oil changes between CI but evidently not close enough!