Stop reading into comments. Nobody's telling you to get the head professionally tested. Everyone so far is saying that THE HEAD IS JUNK. It's a known issue with the #14 casting and very well documented, including photographic evidence right here in this thread.
#14 Head Casting + Cracks = Crap. End. Of. Story.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)