Blew freeze plugs to head???

kinda thinking it would almost have to be a not put in right problem---you are only dealing with coolant passages and not anything where compression should change it and i think if anything the rad cap ,with agge would hold less pressure than more
but who knows weird stuff happens sometimes
with cats--torque is usually so many ftlbs + a turn of x number of degrees

 

it could be a very tiny crack in the head as the piston comes up on the exhaust stroke, it can push out the plugs once it forces it's way into the head. i have had dealt with cylinder heads both aluminum and cast iron over the years and only magna-fluxing can find the problem. stranger things have been known to happen. improper torque sequence, bad cylinder head construction (wasn't cat on strike some time ago..?? how does anyone know if that cylinder head was made during the strike at the time and out aside..along with hundreds of others..??)

yes, "torque to yield" if not done correctly will make for problems at a later time.

a proper compression test, and i would even say a cylinder leakage test as well..those tests if done correctly may take about 2-3 hours, but far more accurate than a laptop saying "no problem".......laptops cannot see everything.

 

i have seen a cat with --a bad injector cup i think it was--it was leaking fuel into the coolant and the rad cap didnt release any pressure--when the guy took off the cap he had a 10 ft geyser in the air

it will be interesting to hear exactely what the problem is--it might belong in the weird and wonderful file

 

Model number of engine would help too where is this freeze plug located on your cylinder head?

 

i dont know a lot about cats--kinda like detroit myself---but could this be one of the engines that needs the liner seat to be cut for liner protrusion?
i wish i knew more about cats

 

Most of the time when a liner cracks the flange like this the liner protrusion is too high compared to the liners along side it.

 

I think I would be pulling all liners recheck there work might have more cracked flanges