2010 Cummins ISX Oil Cooler Plug

I have a 2010 Volvo with a Cummins ISX. I need to get coolant from the engine to create a loop. I have the return plumbed into the block up high at the rear near the head. There is a plug in the oil cooler a little left of center just above the oil filter I'm going to try. Below is a picture same as mine and I drew an arrow pointing to the plug in question. I think this is coolant behind the plug and not oil. I'll find out for sure in the morning. If anyone knows about these oil coolers and their associated plugs let me know. Is there any reason this won't work?

 

I didn't have to use that port after all. i plumbed into the upper rear port of the coolant filter housing. I drew an arrow pointing to the port I used in the attached pic. It's working great now.