I would pull a valve cover off and see if there is milky film inside it. If there is a lot I'd say you need to do additional checking. You can get the car running and up to operating temperature and remove the radiator cap. If you see bubbles in the coolant you have a bad head gasket. You can then do a compression check and see which gasket is gone. If you are lucky it is only a head gasket and not a cracked head or block.

Raul