Well if it is leaking anyway you can't ruin it by trying to fix it - right?
I have always replaced
oil coolers that leak - probably because they have always leaked as a result of a collision. I've never had one just leak.
To see where it is leaking from exactly, make up a mixture of thinner (or something really thin) and put some dye from a leak detector in it. Black light it and you will know exactly where it is leaking from.
I know I am not answering your question.
Pat