Greetings!

I am having a problem with my friends 95 civic, he got a head gasket job a couple of weeks ago and the damper bolt backed out once. I tightened up with an impact gun until the bolt did not move anymore but he called me and told me it did back out again. So i honestly dont know what could be causing it since i did not work on the car so i dont know if everything is put like it should be.

Would an overtightened timing belt cause that to happen? if not what other things would cause that?

Thanks!