Hi Tom,

Above the oil cooler there is an O-ring, perhaps it has quit.  Older ones
were dullish orange-red, new more flexible one is silvery-grey.  Older ones
tended to stiffen and blow-out at startup in winter. Fiddly to replace, but
you should be able to do it without unhooking the H2O lines to the cooler.
If that is the problem.

bye, Tim