I’d been trying to find where my coolant had been going for the past 2 months, pressure tested and never saw any external leaks. I rented an exhaust gas tester for the coolant since it seemed like the degas bottle was being over pressured and blowing all my coolant out. When I left the store with the tool I had some white smoke for a couple seconds, new since I hadn’t seen any smoke previously. Got to work and did my 8 hours but when I went to leave I got nothing. I had a hydro locked engine. I got the truck towed home and started checking what I could in the truck. Found a single cylinder filled. I got the engine on a stand and the head pulled off for an inspection.
Here’s the part I’m at a loss for, I didn’t find any cracks in the block or head or any bad spots on the head gasket. The block was at the machine shop 8 months ago and the heads were remans I got 4 years ago when i initially freshened up the the engine. When I put the engine brine together back in July everything seemed to check out hood and I had no issues for months. Anyone got any ideas where I could have an issue that’s not obvious to see with a normal visual inspection? I’m trying to get a shop to pressure test the head to see what they can tell me about it.
At this point the girlfriend is very not happy with my truck and I’ll admit in kinda crabby too. Anyone have some helpful insite?

 

sounds like injector cup or cracked head under it
testing isnt easy for this one as it can seal up with some heat yet leak when cold or seal up again colder

 

Have the same situation, hydrolock, dont know how/where the coolant got into the oil/cylinder.
Pressured tested at 40 psi and got no bubbles.

 

Definitely not good. The machine shop finally responded so will be dropping the hopefully problem head off Tuesday. Really wanting to see what bad so I can spend the money appropriately

 

Did the water jacket pit through the cylinder wall(s)? It's not common but it's not unheard of either.

 

I didn’t see any spot in the cylinder wall that looked like it had. Cylinder looked intact, head surface looked intact and no noticeable spots on the head gasket for a failure.
I’ll give it a good look over and cleaning in the daylight, planning to drop the one head off at the machine shop Tuesday to have them check it over. Hoping it’s no more than a set of heads to fix it otherwise the truck will have to sit a while and I’ll have to get something else. Still going to buy newer and fix my 7.3 but would like some time.