4.5 l
Thats not right, is it?
The ek9 manual says that it should be filled with 3.8 US qt oil (3.6 L 3.2 Imp qt), it all depends on the coditions (rebuild, new type of filter etc)
My recommendation is to add 3.7 liters of oil, let the engine run for several minutes and check the drain bolt and oil filter for leaks.
Turn off the engine, let it sit for several minutes, then check the oil level, if necessary, add oil to bring the level to the upper mark on the dipstick.
i always seem to be left with approx 300ml or near when using 4 litre container.