Have a 93 Ford Explorer with the 4.0 Litre, have replaced the radiator, all hoses, raditor cap, thermostat, water pump, had a 10 minute pressure test performed and losing coolant. Engine does not miss or backfire no visible signs of where coolant is going. Replacing close to a gallon a week ideas? Do seem to have an abnormal amount of condensation out of exhaust pipe. Think maybe a bad headgasket, cracked head, or intake manifold gasket, just need some confirmation or test I can use to help determine the need to tear into the engine.