Ok… My 2001 Nissan frontier xe… Has a V6 non super charged engine. I have over 138k on it and after a major service it began to overheat on me. A visit toy mechanic 2 months after revealed a worn by pass hose, it was replaced. The water pump was also replaced at the service.
The past three weeks the vehicle continues to overheat. I have replace the thermostat, several hoses, clutch fan, radiator and sensors . After all this still have bubbles in the radiator. I have had two pressure test and two checks for co2 in coolant both were negative … The engine runs like a champ … No smoke no sputtering purrs like a kitten… Yet after a drive on the high way 40 to 60 mph… I end up with it over heating and bubes in the resivior tank. There is mo coolant in the oil and no smoke coming out the exhaust …Help!