Coolant in oil

[DasAutomatik]

Hi I’ve got 2011 cm871 with about 40k on an out of frame new head and reman block if it matters. I’ve been losing coolant and the the past 2 oil samples show eleveated sodium levels. Been battling this for a while since the out of frame. Oil always looked good no milky or slugging. I dropped oil pan and pressurized the cooling system to 13-14 psi and saw tiny bit of coolant coming out of a galley on the passenger side of the block near the back. I brakeleened and dried out all around cylinder to confirm coolant wasn’t running down the liner and into the galley before it ran down. Couldn’t really see anything with a borescope as far as cracks go. So I drained coolant and pulled the oil cooler off to see if there were any cracks on the block or gaskets for oil cooler. Everything seemed fine. Granted oil cooler was replaced about 10k mi ago. Also truck was de mandated about 3k mi after rebuild. Egr cooler was removed and i replaced it with that water bypass tube to keep coolant flowing to the rear. Vgt is still intact. Any help would be appreciated