Good Morning All. I have a 2001 Grand Prix GT (3.8 L Vin K) And have noticed oil residue in the coolant resevoir tank, for about a year now. My concerns are, the engine oil is being consumed quickly, and I need to add oil about every 2 weeks or so. And, the coolant level drops also. There are no signs of coolant in the oil. Just oil in the coolant.