With car on flat surface drained the oil as usual and approx only 5 quarts came out. Changed filter and put back approx. 7.5 quarts and now the gauge is alteady showing full. Any ideas? Will drain soon again to measure exactly how much will come out. I suspect oil level sender. Is this easy to reach for replacement or any known issues?

 

If you only drained out 5 quarts and put in 7.5 quarts why wouldn't you expect it to show full? How far below full was it before you drained out the 5 quarts? IIRC, 7.5 liters added at oil change typically ends up pretty much filling up.

 

Before draining it was showing full and that is why I suspect the sender.