What size is a 10x9 flange nut (holding the starter motor)

Can you take it with you to match it up or go by a pull-a-part junk yard and pull one you need. Match up thread course or fine, we have a Ace hardware store and I replace bolts all the time, But you also have to get one rated for the strength you need too.

I lost the nut and the bolt is part of the flywheel housing, I can't take it out. But I am going to the junk yard this weekend !

There is a pull-a-part near me, sometimes go there and pull a box of junk that may need to do any repairs then or in the future or may see something in better shape then mine, they sell most items by the pound so its always dirt cheap.

Take a picture of the bolt it may help with finding the nut you need if you have to stop by a hardware store.

Did you find out what the size was? I have the same issue with a 2018 Crosstrek