Repair 4 diesel

OP, I know it's probably too late but if it were me I would have the oil cooler replaced along with the EGR cooler if you want to keep it on there if not delete the EGR cooler. This will give you a much better chance at keeping the heads on it. What causes the heads to go on the stock 6.0 is the oil cooler's coolant side gets clogged which starves the EGR cooler of coolant. The exhaust gasses that run through the EGR cooler then will melt the inside of the cooler allowing coolant to enter into the intake manifold in turn getting into the combustion chambers. This causes a hydra-lock in the cylinder on the compression stroke that will stretch the head bolts blowing the head gasket. If your truck does not use coolant to where you have to put coolant in the degas bottle every so often then there is a good chance you can save your head gaskets by doing this. I have a truck with 320,000 miles on it with original heads, gaskets and bolts and another one with 290,000.