1998 Buick Century • 157,000 miles

I recently acquired a 1998 Buick Century Limited 3.1 Ltr V6 from my sister and her husband as they were getting a new car. When I checked the oil it was 1Qt over full and clean, the trans. Fluid was ok and also clean, the coolant reservoir was empty, after driving it for a few days I checked the coolant reservoir again, it was brown and slimy as if contaminated with oil, does this mean I have a blown head gasket, or could there be some other reason for the brown slime. My brother in-law said he once put the wrong coolant in the radiator and reservoir but his mechanic cleaned it out.
March 4, 2013.

Based on what your vehicle is I would say that your lower intake gasket is leaking, it is a very very common issue with tese motors, the lower intake gaskets fail and they can leak oil or water or both and either internally or externally or both.I would suggest that you pressurize the cooling system and try to locate any leaks.

Mar 4, 2013.