Usually Coolant is not found in the oil on a Head gasket failure of minor degree. Coolant in the oil is typically found with a major blow out, like the head gasket is pukeing coolant in to the cylinder. So one would find coolant upon removing the spark plugs and trying to do a compression test.
So some other hints for finding cooling leaking into the oil pan. Put a dye into the coolant, use a cooling system pressure tester, remove the valve cover and look for the dye. I have found the casting broken around the plugs in the valley of the cylinder head, leaking cooling between the front timing cover. And then If I could not find any other place, remove the oil pan and look for dye. If not then suspect the oil cooler. But the oil pressure is usually higher than coolant, so usually oil gets into the cooling system, not really the other way around. Lots of work to sometimes find a coolant leak. Anyhow good luck with this.