Although already mentioned don't forget to check or change oil pressure sender before getting inside motor.
Question with low oil pressure did motor sound different at idle,tinny or lifter noise?
My 300CE with about 225k started to go to a little less than one bar at hot idle and turned out to be sending unit.Got real lucky and had a good used sender to try.
Good Luck
Rich

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88 300E White, sold 9-04
88 190E Black 2.3 sold
90 300CE White, Grey sold 12-24-04
92 400E White,Grey Sold 5-06
90 300CE 91K Signal Red,Black Sold 2007
1989 300CE Smoke silver,Tan Sold 1-08
1993 300E 3.2 M104 motor
1991 300CE White,Grey
1994 E420 beautiful car,gone to new home
1994 E320 Smoke an Parchment.Beautiful car