Found oil in cooling system, removed oil cooler, gasket looks bad, any other things to look for on the cooler to tell if there are other problems? also suggestions on where to buy a new cooler and gasket? and the best way to flush oil out of cooling system?

 

Cummins or Dodge, or used.

 

I would say whatever is going to be the best replacement for the $, but I think I am going to stay with a new one.