Stripped inside of the 13mm bolt connecting the camshaft to the head

[Jako212]

A Helicoil should be just fine for that. To use one, you'll have to drill out the hole and re-tap it to a larger size before inserting the Helicoil. Just be careful to monitor the depth of your drill bit to avoid breaking through the casting. Also, tape off anything that shouldn't get metal shavings in it.

It should be an easy repair, just take your time.

I see , how can i know the specs of this bolt so i can find the right size helicoil for it

[McGyver]

I see , how can i know the specs of this bolt so i can find the right size helicoil for it

You can use realoem.com to find part specs.

https://www.realoem.com/bmw/enUS/showparts?id=1113-USA-03-1989-E30-BMW-325i&diagId=11_0405

So #6 is a an M8x25