I broke two head bolts on the exhaust side.

#5 snapped off where a thread had about a half turn of corrosion. It backed out with a drill and extractor.

#1 was dry but red and rusty. It will not move in the hole. This is a dire situation.

Are these threads tapped into bare aluminum or did volvo use steel or stainless thread inserts? I am considering dissolving the stud with alum solution.

 

If i remember right, and someone correct me if i am wrong....but it all aluminum. i would drill it out and retap. its what i did on my intake manifold.