My 7.4 MPI is supposed to hold 6.6 litres, but I only got 4.3 out of the dipstick tube with an extractor when I did the oil change. I know there was 6.6 litres in there because I just rebuilt it and put that much in there. I am reading on the forums that this is a common issue. Any ideas why I can only get 4.3 litres out of the dipstick tube? Is there that much oil caught up in the engine and oil cooler, etc.?