Thanks for the input about cracking.
The cooler/adapter assembly is a bugger to get off, The water return to the block was the problem child for removal. I got a mechanic to come over for the removal. Glad I did because it took him an hour to get the unit loose.
Anyway found the oil return line 'o'ring to be the culprit, cracked and fairly stiff,
Replaced 'o'rings and reinstalled. Waiting on turbo gasket which is available after 6PM. Then I can add coolant and check for leaks.
BTW 7 degrees outside and wind of 20MPH.
Bill, who should be in Florida by now