Where the EGR passes through the Upper mani, it erodes the wall clear through to a coolant passage. When that happens, coolant enters the intake then the cylinders. Depending on the size of the hole, it can use just small amonts of coolant, and make smoke, or large amounts of coolant and fill up a cylinder or 6 with coolant really fast and destroy piston rings or other important components of the engine.
A 180 will keep it cooler and proling life of the upper intake. There are redesigned manifolds and kits to fix the problem permanently.