did u know that before u went to go look at it?.. its just one of those things. i doubt the seller knew it either. i only know it because my neighbor restores bmws, and i help him alot.. and i just have seen how these cars are.
Most people look for obvious signs, like milky oil/coolant, and white smoke...
not picking sides.. but it happens.. and old cars suck...lol
we told the guy that we had no clue that it had a fucked up headgasket but he kept on cussing and what not. after he had enough he just hung up.