Coolant in the Engine Oil- Cat 943

Hello All- This winter I noticed that coffee-colored oil was slobbering out of the oil dipstick tube on my 943. Oil quantity was over-full. I dropped the belly pan and drained the oil. It was somewhat discolored, but in the drain pan it looked almost normal. The service manual says that if you find coolant in the oil, the first move is to replace the oil cooler. The R&R on this $355 cooler is no big deal, but I would ask your opinions on what is going on in the engine (3204), and what I may find when I unzip the cooler. Also any ideas on precautions I might take when I refill engine oil and radiator on restart. If the cooler is eliminated as the problem, the manual says to check the head gasket, cylinder head, and block, (say it ain't so!) Thanks for any input. Regards, Clark

Coolant in the Engine Oil- Cat 943