Only ever heard of diesel being used to free a seized engine... bearing in mind that a kill or cure option is better than a total loss.
Engine was a rolls royce b80 military in a Saracen armoured car. Only way to get it out was to completely dismantle it or cut the hull open, and electric weld it back afterward. On an eleven ton armoured hull it could have been expensive on a tight budget. So all eight cylinders were fuel filled with the plugs out, a starting handle inserted and a jack applied to bring pressure to bear and left to stand for a month.
For reference. When pressing starter button with batteries connected make sure no-one is standing next to the engine downwind on the spark plug side as dry cleaning bills are an additional expense.
...heaven help them if they are smoking...
Last heard, engine still running, ten years on.

Al