I have driven a 300CE about 4000 miles since I bought it from my father, the car has about 335,000 miles on it.....I noticed two days ago that my oil pressure gauge has been showing lower pressure every day.....

On start up (engine cold) I read 3 bar, after warming up to 80 C at idle the gauges bumps off of the low needle and reports 1.5 to 2.0 bar at highway speeds.

I pulled the sender cable off of the unit with the key in Position 2 and the gauge reads solid 3 bar, so it is not a bad gauge...I am going to put a manual gauge on engine tonight to confirm oil pressure.

Are there any other diagnostics I can run...

TIA

Start by changing the oil filter! IT can cause that problem!

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MERCEDES Benz Master Guild Technician (6 TIMES)
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27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
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thanks, I will try it first...I just noticed that it is a generic filter non-oem....must be part of the problem

M.B. Doc....A big

Changed to a WIX filter, oil pressure indicator back to normal

that is great! No real $$ spent! USE a Knecht/Mahle OR Mann filter!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator