I have just finished rebuilding the oil cooler on my 2002 7.3. I had no problems, everything went together and back on the truck without any issues. I used Dorman parts and I used regular hub grease to make it easy to slide the cooler back together, I was able to do so just by pushing it by hand. I filled the coolant and oil back up and cranked it. I let it run 5 or 6 minutes and then shut it down. When I checked the oil, it had a small amount of coolant in it. I drained both the coolant and the oil. I left the filter and drain plug off and refilled the coolant. I'm getting a few drips of coolant from where the filter mounts, from inside, in the very center of the threaded tube. There is not an external leak that I can find. Is there something I'm missing that's allowing the coolant to pass into the oil? I'm about to recheck the torque I put on the bolts that hold the cooler to the block. Any other ideas? I'm tired, wet, aggravated and stumped.