keuper

I pressure tested cooling system with injectors out,sprayed soapy water into injector bores and found cracks in the head just above the cups at cyls 1,3 and 6...but i still have no idea where the little injector screens disappeared to.Thanks Keith.

im working on our rv departments f350, it came in with coolant leaking,blowing out degas bottle,and a terrible fuel smell.the driver admitted he overheated it.it ran just fine no miss,contribution all normal,but had fuel in coolant.so i tear into this thing,pulled injectors and found that 5 of the 8 injectors have missing or torn screens at the injector fuel inlet.the injector cups look ok.my question is what caused this??fuel press is 68psi/59 psi sim wot.fuel lloks good/filters recent.ive seen one injector with a torn or missing screen before but 5 of 8??? what do you think?