Help diagnose low oil pressure problem on 528e

[hnng <hnng@xxxxxxxxxxxxxxxxxxxx>]

Hi all,

A few days ago, the low pressure oil lamp came on for my 1982 528e.  The
car is currently at my mechanic's shop but they cannot figure out what the
problem is.

The oil level is fine, the head is not cracked nor is the engine making
any funny noises.  A pressure test has indicated that the pressure is
indeed low.  What can it be?  Oil pump?  Any suggestions are appreciated.

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