On April 15, 2019 at 09:52, highfigh said...
If it's a GM clockwise rotation engine, the nut is left-hand thread, which ensures that the engine's rotation is always trying to tighten the nut. Put an open-end wrench on the nut and hit it with a hammer or dead blow hammer in the opposite direction and it should become loose. If not, give it a shot of PB Blaster and wait 15 minutes before trying again.
Heat is what worked for me