oil getting into my coolant system

Recently found a oil sheen in my coolant. I think it has to do with when i was installing a March alternator bracket system on my engine as I did not get enough sealer on the thread of the bolts or the incorrect sealer. I am not getting coolant into the oil so I suspect it is heating up hot oil is migrating to the coolant system around one of the bolts that hold everything together. The top 6 bolts that hold the timing case cover on needs sealer Nothing else looks out of place. Please advise Thanks in advance Texas Red.....