I also suggest pulling that bolt and having a look at it. Is it possible that you dropped some gasket material in the hole as you were scraping things clean? It may not have come out when you blew the holes out. I would dig around the bottom of that hole with a long screwdriver and see if there's anything in there. You can also use some kind of a rod to measure the depth of the hole. Compare that to your new bolt and make sure you have some clearance without bottoming.

Hopefully the bolt threads gave way rather than the block.

I'm less optimistic than Paul about the gasket still sealing up properly after 10,000 miles of use, but I'd sure try it before re-doing the whole job!

__________________
D.H.

04 ML500
02 E430

Experience is something you don't get until just after you need it.