1990 300CE Low Oil Pressure

[cws3rd]

Hey All,

I have an M104.980 engine that has strange oil pressure readings. After warmed up, it shows 2 at idle and climbs to 3 when revved = normal. When in gear and accelerating strongly it drops to 0-1 until I let off the accelerator. Also, when climbing hills it drops to 0 for several seconds until I let off the pedal.

Are there pressure valves that need to be cleaned (which ones and where?) or should I replace the oil pump? Car has had the oil pressure drop-upon-accelerating condition for many years. Installed new oil pressure sender last year = no difference. Also, there is a definite change in the sound and temps when climbing, so definite reduction in oil pressure, not a sending unit or gauge problem. THANKS!

[Sugar Bear]

Sounds like a problem with the pickup/screen???...at idle (I'm assuming level ground) it's ok but on hills and acceleration it drops. Sounds like the pan is going to have to be removed unless you can put a borescope in the drain plug hole.

Please post the conclusion I'm curious as to what you find.

How much oil is in it 7-8 qts.?

Good luck?

[Stretch]

Do you have to add a lot of oil due to leaks?


Do you burn a lot of oil?


And at the risk of starting a famous WW3 peach parts oil thread - what grade + type of oil are you using? Do you use snake oil?
[Oh oh oh! This is so asking for trouble!]





I must say if this has been a long term problem the chances of serious wear sound quite likely to me

[Sugar Bear]

You also may get a look into the pan through the low oil level sensor.

[ILUVMILS]

I'd verify the pressure reading with a mechanical gauge before tearing anything apart...........