I have never heard that synthetic "clings to surfaces" and takes longer
to drain but I do know that synthetic oil will sneak past worn gaskets
or valves much faster than conventional oil, which is why I didn't
change to synthetic on my 150k 525i. In my experience, synthetic flows
quite rapidly especially in cold weather.

- Scott




"Jan Fure" > wrote in
oups.com:

> Since I filled my 1991, 750iL with Mobil 1, 0W-40, the low oil level
> alarm has started going off when the (overnight) dipstick level is 1/4
> of the way down from the high mark.
>
> I have heard that synthetic oil "clings to the surfaces", and thus
> takes longer time draining to the oil pan compared to conventional
> oil, and this seems like a confirmation of that. It probably takes 6
> hours to get a repeatable oil level reading, prior to that, the level
> slowly increases.
>
> Has anybody else seen this, and if it is true that synthetic oil
> drains down slower, would the optimal oil level be higher than for
> conventional oil, or would the risk of overpressure exist during
> startup?
>
> Jan Fure
>
>