If you dont change the oil, what problem can happen? I change the oil every 3000 my husband says that is STUPID, I always have with all my cars, now he never does and has messed up one of my cars and says it isnt hes fault. I say it is. Please help! 10,000 miles since last oil change, now water in my oil. 2 1/2 years ago had the engin redone so should not have this problem. Help!