I've done the blown head gasket thing after loosing all the coolant. If that's what happened to the other one and that's why the head gasket is blown you will be needing a new head. If it was just oil leaking into the coolant or vise versa, you can usually just take the head off,new head bolts and gasket; throw it back together and you're as good as gold.If lost all the coolant and new head at minimum. If it were me, usually the rings are toasted as well. I'd be starting from scratch will a full teardown... If it were me I'd look at how bad the one you're buying is first.