Thanks guys for all the input on my query about the head bolts. Through a local tool supply house I found out that the head bolts are not a torx, they are similar but not the same. The right tool for the job is an 12mm Serrated Wrench for 12- point metric socket-hesd screws. I quest that only an MB mechanic would know that. How does the old saying go? The right tool for the job. Regardes Karl