Cooling issue on highway

Meh, I like mine in the 170-180 range.

Hey as long as you like it who cares what your engine wants?

Yeah but lord hammercy. 16psi sure doesn't do the cooling system any good. I have a 13 on mine. I try to run as low a psi cap as will work. Nice and easy on everything.

The 6.4L GenIII this thread is about probably had an 18 psi cap at the low end, might have been 21 psi. Even a 12 psi cap still puts the boiling temp of plain water at 242°F. And if you're running a 50/50 with antifreeze its more like 259° (16psi 50/50 would be 267°).

Regardless, nothing it going to be hurt running that engine at 200°F, absolutely nothing. It will probably run BETTER.