2014 Peterbilt 367 Dump Truck! My First Truck and Need Your Help!

[Squish099]

The circle you pictured is just a cap in the front cover. You are correct if you pull it it it reveals the 3/4" square drive used to bar the motor over. I would never accept someone saying something was done. Did he say egr valve or cooler? The cooler is the square thing that sits down behind the turbo mounted to the block. If it was leaking 90% of the time is wipes the precisious metals off the filters rendering them useless. Need to check for blowby. What's the breather filter look like?