Those are very cool. I have some clone Gearwrenches from Harbor Freight but they are flex head not indexing head like those. Have not seen that before, already looking on ebay. good tip

 

I hear you. But as I mentioned, I've had the manifold off a few times before, as the RTV between the block and intake manifold tends to "cook out" every 4 years or so. I'm the original owner of the car, and on this car, these are the OE nuts.

 

Nuts shrink as they age.

 

This is correct, a 13mm socket is 0.3mm bigger (0.0118"). However a 12 point 1/2" socket can be looser on the same nut than a 6pt 13mm. I guess that would go to manufacturing tolerances.

 

Don't I know................












Good point. I think the 13 MM I have is indeed a 6 pointer.