When I first starting using an extractor, I removed the drain plug a couple of times after extracting just to see what else I would get out, and I got either nothing or next to nothing. There is always a little bit of old oil in an engine after an oil change and I assessed that the very small amount that I might add to that by using an extractor was negligible.
There is nothing wrong with either method.
BMW pulls the plug, Mercedes dealers use extractors.
BMW hasnt had dipsticks for 12years, and many Mercedes do not have drain plugs anymore.
If your taking care of your oil and using the correct standards than you will have normal deposits occuring in your engines and whats on the bottom wont be an issue. API standard are an evolving platform - API SL is older tech than SN oil and there have been 13 generations of oil technology.
Oil doesn't sludge like it use to anymore - but can should you "burn" it by running it too hot (oil to low) or fail to change it before the additives that control the oil stability wear out; or reach the limit of its ability to hold the contaminants in suspension ie: gas and carbon from blowby.
Use the right oil from the start, watch the level and color and change it yearly minimum (anti corrosion additives have time limits). And dont let it get too dark - black is WAY too late to keep a healthy engine. Think of it like toast and your engine is the toaster. You put in the pale bread and take it out before its dark brown or black.
I have some tips.
- Pack rags aroung the filter housing for drips and spills.
- Dont reuse the o-ring.
- Add a safe load of oil initially (dont exceed max on the dipstick unless you already know how much it needs - its not always linear above the max marks). Run the engine for 15sec and turn it off to let the oil drain back down. Then clean up, 5w30 can take 20min to settle. 0w20 wont take as long.
- Want to know exactly how long your favorite brand takes to settle? You know that little bit of oil in the bottom of the each bottle? Turn a bottle upside down and start a timer and when the bottle doesnt have a little puddle inside it anymore then thats how long it takes inside your engine to return to the pan (at that temp) and is the time you should wait to check the oil.
- everytime you add oil you should be waiting! So add the right amount once. In case you didnt already know - the difference between minimum and maximum on a dip stick is 1 quart unless marked otherwise. If your readin in the middle, add 0.5qu.
- Do not overfill. If you love your engine, remove the excess. Even a slight amount overfilled causes strain on the crankcase breather system and you'll be creating more pressure inside your engine that can eventually cause leaks. the volume inside the crankcase is engineered for the PCV system ability to vent blow by gases. Reduced volume increases pressure, Positive presure inside a crankcase causes poor oil ring sealing and oil comsumption and stress on your seals/gaskets. Note the opposite is true also - BMW uses vacuum in the crankcase and increases oil control and reduces oil consumption.
- beware additives! Theres a reason No manufacturer recomends additives, its adds an unknown factor. When you add anti-friction additives to anti-friction additves guess what happens? You get an increase in friction! This is a real thing and unless you KNOW your favorite additive is helping, it is safer to avoid using any.
- Porsche has a standard for oil changes. Oil temp above 90c(194f) and drain until there is 1 drip every 10 seconds. This is considered empty.