Oil change via suction vs normal

Hi Guys,

About to do my oil and filter change on my Mercedes ML550. Previously I've used a Mityvac suction tool.
I was wondering if changing oil in this way somehow leaves oil behind at a low point that may accumulate sediment. Or does all the oil in an engine end up going via the filter so all oil in the engine is clean?

Just wondering if I should do a normal change now and then. Also with the Boxster is the suction approach okay?
(A lot of mini service Garages near me have industrial suction tools making it even quicker to change oil if this route is okay)

Cheers,

Quote
ouroboros
Hi Guys,

About to do my oil and filter change on my Mercedes ML550. Previously I've used a Mityvac suction tool.
I was wondering if changing oil in this way somehow leaves oil behind at a low point that may accumulate sediment. Or does all the oil in an engine end up going via the filter so all oil in the engine is clean?

Just wondering if I should do a normal change now and then. Also with the Boxster is the suction approach okay?
(A lot of mini service Garages near me have industrial suction tools making it even quicker to change oil if this route is okay)

Cheers,

extraction but currently none of the Porsche engines are designed with this in mind.

Now one of my auto dealer contacts (an Audi dealer) tells me the new Audis will have this feature, the engine -- I've been told but have not been able to confirm this yet -- will have no engine oil drain plug.

The problem with using a suction technique with an engine not designed for this is the engine oil sump is not designed for this. There is no special sump that is intended to accept the end of a suction hose, the engine doesn't have the tubing to route this hose to the precise location it needs to be routed to.

The result is the hose ends up where it ends up. It might not get all the way down or it might reach botton and bend/curl up.

As a result the amount of oil removed varies.

For those cars with the digital oil level sensor/sender it makes it nearly impossible to 'test' this sensor's functionality/accurancy because the technique for doing this requires the engine be up to temp, the oil drained for a certain amount of time, and then a specified amount of oil added and the level checked to confirm the level reading agrees with the quantity of oil added to the engine.

Any residual oil pollutes the fresh oil. Now there's always going to be some residual oil left in the engine and the residual oil of course mixes with fresh oil will get filtered so there's no real concern about that. The concern is the fresh oil's additive package is to some level compromised by the extra amount of residual oil the suction method can leave behind.

With the way the oil changes are done now, by draining the oil, Porsche has many thousands of hours of engine run time to know the amount of residual oil left in the engine does no harm. (Ideally all of the residual oil would like to be removed, but that's for all purposes impossible.)

It is your car and you can take the car to any place you want and have the oil changed anyway you want but I would never use a shop that used a suction method to 'drain' the engine oil of my Porsche engines.

Sincerely,

MarcW.

You simply cant get all the old oil out, nor will the "rush" of hot oil (yes, i change with it hot) sweep out the dirt that accumulates in the bottom.

I also assume that the suction can't really get to the very bottom, so some oil, dirt, acid, and mixed in gasoline remains.

You do change 95% of the oil, but you may leave 10% or 20% of the sediment. Who really knows? Do it right.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com