Just wondering.

Made me think about the guys using the "oil sucker tool". One reason discussed was getting more oil out. Does the amount of oil left in the heads pretty much negate the extra oil you "suck out".

I don't know. But on my MB inline 6 engine with 7 litre fill capacity the check valve holds nearly 3/4 to 1 litre of oil within the engine. But the valve can be released during oil change be it bottom drain or suction extraction. Most tech actually use compress air to facilitate the drain process. This engine uses the top mounted cartilage filter and the valve is up high. Not sure about the Audi design using spin-on filter.


C.F.