first check the oil to see if it is making choclate milk if not fill the rahiator and presure test the cooling sys to see if it holds ptrsure if it won't hold presure look fore and repair any external leaks if none are found pull the spark plugs keep the presure on the cooling. WITH THE SPARK PLUGS STILL OUT have someone crank the eng and watrch to see witch cyl spits at you. P/S if you don't have a radiiator presure tester and don't want to buy one many auto parts stores will loan you one if you leave a drposit