Look at you're oil cap ware you put oil in and If you see like a frothy look to it you probably have a bad head gasket you can also look at the dipstick and if its higher than what its supposed to be you probably have a head gasket problem. If it is a head gasket when you take the head off take a really straight and flat peace of meateal and go slowly across the head in all directions and if you see any gaps even a little one take it to a machine shop and have them shave the head otherwise if you just put a new gasket on it will still leak also look for cracks . You could have them preasher test it as well it should all cost about 60 or so.