The Engine sit undisturbed in the engine bay and its difficult to check underneath without lifting it out but perhaps we should do this more often. I change the filters and replace the oil on a regular basis sucking the old oil out via the dipstick entry, it never occurred to me to check what’s going on underneath until I arrived to find the bilge full of Oil. first thought was a hole in the filter due to corrosion nothing obvious fortunately the boats on its trailer undergoing maintenance so I lifted the engine out using the trusty Merlo to find the cause of the leak was a hole in the sump where it had corroded through.
Ouch! Glad you were on the trailer and not punching off a lee-shore under engine!
I am going to check mine now….
I had never heard of sumps rusting through until I recently bought a ridiculous French car, on which a number of owners have had similar problems. In this case French steel not being able to cope with English salt.