I’m looking for some advice on my 2005 Grand Prix GTP. It has the 3.8L, supercharged V6. It currently has 109k miles. Since it turned past 105k miles, it’s begun to use oil. So far, it’s used 3 quarts in 4,000 miles. I am taking it to be looked at next week, but there is no evidence on the garage floor that there is an external oil leak.
Does anyone have any advice on what could be going on, or how to fix it?