I round a Pontiac Grand Prix on Craigslist on a dealership. I went to look at the car and the guy said that the Intake Manifold Gasket needed to be replaced. However, there is water in the oil which leads me to believe that the Head Gakset is what is bad on it. I do not believe that a bad Intake Manifold Gasket can cause moisture to get in the oil. I need to know 100% what is wrong with this car before I can buy it that way I know how much money I have to put into it. Any advice helps. Thanks!