[marswill]

My stiffener bar under the hood kept getting loose as the bolt was partially stripped and couldn't be torqued down very hard. I've now rethreaded the M10x1.5 threads with Helicoils purchased on Amazon. The result is that the threads are now as good as new, no, actually better than new as they are now stainless steel rather than aluminum. I can now torque down the stiffener bar enough that it will no longer come loose.
The item is:

 

[JCMorrill]

Would you post a picture of the part you're talking about under the hood?

 

[Harleyguy]

The two cross bars that go from the firewall to the strut towers . It also has the black bar from side to side to the strut towers .

 

[marswill]

My stiffener bar under the hood kept getting loose as the bolt was partially stripped and couldn't be torqued down very hard. I've now rethreaded the M10x1.5 threads with Helicoils purchased on Amazon. The result is that the threads are now as good as new, no, actually better than new as they are now stainless steel rather than aluminum. I can now torque down the stiffener bar enough that it will no longer come loose.
The item is: http://www.amazon.com/gp/product/B0002SRF80?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

Here's a picture showing the two T50 M10x1.5 bolts that I added the Helicoils too. Also, when I cut the Helicoil threads I use a cutting fluid to insure I got real clean threads before adding the Helicoils.