[JTyan]

Alright, I'm sure this has been a thing alot with the Lb7 but mine had been light hazing the past few months, recently been losing coolant somewhere, no visible leak. Today I got to work and low coolant warning came up, shut off truck and topped up tank. Truck sat all day then when I went to go home truck only rotated over a quarter turn like the engine felt locked, noticed the tank was empty again, so I'm guessing coolant drained into a cylinder and is keeping truck from turning over. Now, could this be an injector cup lifted or head gaskets? It sucks because it's my good vehicle for traveling and hauling hay for my animals. But going to have to tear down and do the work myself due to lack of funds to be able to pay someone to do it. Just need to know where to start and what to look for. Going to let it sit a couple days and maybe it will kick over so I can at least get it back to my farm. Any ideas would be super helpful.
2003 Chevrolet 2500HD 6.6 Lb7
155,000 miles

 

[GoBlowSnow]

how many miles

 

[JTyan]

Edited 155,000 miles

 

[DMAXfirefighter]

Lifted cup and blown head gasket present with the same symptoms. Did it ever present hard hose? After sitting overnight, still having the upper radiator hose hard when it should be soft after sitting? If you had a small and then suddenly turned into a big leak and hydro lock situation the way it sounds, I fear it’s bigger issue than head gasket or lifted cup but maybe not. DEFINITELY get the heads checked and decked while it’s apart

 

[roachwe]

Do not try to start engine with water in a cylinder unless you want a bend or broken rod. Remove glow plugs to locate the bad cylinder. Drain water and then remove that injector to verify if cup is loose or not.