Hi I am new to your forum and am looking forward to using the site on a regular basis. I own a 1990 911 C4. I just changed the engine oil and added a total of 11.5 liters. According to all the info I have read this is too much oil. The dipstick showed the oil at the top mark. The oil level gauge was also reading good. I read that it should take 9.5 liters. With 9.5 liters of oil in the engine it is not even at the first mark on the dipstick and the oil level gauge is at the bottom. The engine was at temperature when I checked it with the engine at idle. If anyone has any idea what I am doing wrong please let me know. Thank you.