a cylinder leak-down test should tell you the condition of your engine and or head gasket...what are your symptoms??? is the radiator blowing coolant into the overflow bottle after you turn it off, is there white foam buildup under your oil fill cap,does the oil look like chocolate milk,and/or is there oil in the coolant///these are typical signs of a bad head gasket and or other problems cracks ect.... check your local autoparts stores some do rent leak down testers..and if this is the route you are going to take repost and we will give you instructions on how to do a leak down its very simple...