Head gasket ! Maybe ?!?!

[GUY325i]

Hey Hey, Ive got a 1988 face lift 325i and it chucked out a little bit of blacky coloured smoke tho other day so being paranoid i checked the oil and when I removed the oil filler cap i noticed a little tiny amount of a dark coffee coloured mayonaise type stuff,Which usually suggests the head gasket, BUT ive checked the compression, Fine. Not using water, Fine . temp gage sits at just below the middle as always and doesnt fluctuate weather you drive hard or normal, And it still goes like a train and will pulla house down
Ive spoke to a former bmw technition and he mentioned something about some little metal item in the engine which corrodes and lets the water mix with the oil??
any idea's folks.
I dont really want it to be the head gasket nor do i wanna be pulling the head off if i dont have to
And if i do have to i wanna be buyin a 525e coz it aint gonna stay standard if ive gotta spend money on it, so if any one has any idea's please help me
p.s any 1 know of a good enginged 525e or engine its self.
once again many thanks

[Toby_Unna]

if it doesn't overheat then forget about it! in cold weather it's not unusual to get a little condensation in the engine leading to mayo on the filler cap. it looks worst on the cap because that's the coldest part of the engine so that's where the water vapour condenses to.

black smoke could be engine wear or fuel mixture-related, wouldn't worry about that either unless it's using a lot of oil.