Seeing that it is so clean underneath, it could be the result of a rodent nest.
To properly repair, the hood, LH fender and windshield would need to be removed so that a proper patch can be welded in and smoothed out.
__________________
1976 LeMans B09 Freeway Enforcer, 455/M40 Smokey
1977 Trans Am, 400/M21 Black/Gold Bandit. 44K actual miles
2017 Sierra SLT 1500 Z71 4X4 
2019 Canyon SLT Crew 4X4 
|