e28 occasional valve clatter

[Poland1 <polands@xxxxxxxxxxxx>]

Ok now I'm worried.  A few days ago after a frosty night, one of my
valves, or some part of the valve train started clattering (not
"ticking") as I was backing up out of my driveway.  My guess is that
some part was sticking, rather than following the cam properly.  I
ordinarily do not "warm the car up", but rather get going after
starting, buckling up, and checking visually around the car.  Since this
noise caused immediate concern, but I was now blocking the street, I
slowly moved on at low throttle, and the clatter was gone within a few
seconds.  The noise has occured for just a few revolutions on two
subsequent occasions, only on initial morning start up.  There is no
such noise after these few seconds on initial warm-up, and the car runs
smoothly.  It has regular oil changes, and is on Castrol Syntech.  I
usually top up 1 quart between service indicator light dictated oil
changes.  What is happening, and what is recommended?

Steve Poland
'88 535is (165,000 miles)
Portland, Or.

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