Oil Pressure Falling
 

Hi,

I did a search and the oil pressure is within the tolerances specified for the car. My question is it seems it has lowered a little since I have owned the car (about 5 years).

Is this a symptom of using synthetic oil? (Mobil 1, 15-50) Does the sending unit for the gauge need to be replaced? Is this a sign of bad things to come?

The car is a 90' 300CE, 124 coupe, M104 I6 24v motor. The oil pressure when I bought the car was around 2, maybe a little above. The reading now is 1 1/3 to 1 1/2. Both measurements taken with the car fully warmed up in drive.

Curious what people thoughts are. Should I be nervous? Thanks for your input.

oil pressure
 

Dean;
Assuming engine is at idle on oil press you stated there is'nt a problem.
As long as oil press is at 3 bar when above idle things are great.
MF

The owner's manual will tell you that at idle, in gear, oil pressure needs to be at least 0.3 bar. Mine tended to be about 0.5 in really hot weather, AC on, in stop-and-go traffic, with conventional oil. Now with Mobil 1 15W-50 it's always above 1 bar under those conditions.

As long as the pressure rises to 3 bar once RPMs get to be above about 1500-1800, you're OK.

Thanks for your reply's.

The oil pressure rises as soon as you elevate from an idle. Its within spec, and has never fallen below 1 1/3, even with the a/c on in the heat.

It is lower than it was when I first bought the car so I didn't know if it was a sign of things to come.

Thanks for your re-assurance.

Even though the engines in my Benzes are diesels, they have the same oil pressure gauges. When fully warmed up the oil pressure will, at idle in park, be at 1.5 bar. There have been times when even after driving on the highway, the oil pressure only went down to about 1.8-2 bar. As soon as the rpms get to 1200 the oil pressure hits 3 bar.