7.8L Fuel Migrating Into The Oil

Hello, I have problem I've been chasing and need help from gentleman like yourselves. 7.8L Duramax 6HK1TC I'm having fuel slowly fill my oil pan up (about 1/2 quart per week) and I can't find the source. I have replaced all injectors and the fuel pump already. Do any of you know where else the two could be coming into contact with one another on a 7.8L? I'm leaning toward pulling the valve cover again and inspecting the fuel return line once again, other than this I'm out of ideas... Any help would be appreciated.

Thanks

Welcome aboard!

With that volume, the return line(s) and/or fitting(s) are the usual (first) suspect.