Flyhard,
To prevent a warm or hot start on a pt6 installation, you must spin the engine or let it cool on its own, for instance on a twin, you would simply crank one engine after you chock in, then the engine you initially start is used to crank the second engine, not complicated.
On the Garett engine, I'd say with 8000 hours on MU2 / Metro aircraft that I know something about the subject old chap, initially, old engines did have a shaft bow problem that could bind the engine up if not spun after a period of 15 to 20 minutes after shutdown, this is no longer a problem, but a great way to cool the engine if you are doing a quick turn.
Cheers.