Constant oil pressure
 

I was in the Tech section where this question was posted, and I have the same question. In my '72 the oil pressure gauge always reads 3 bar. Even when fully warmed up, at idle, in warm wheather (yes, I mean fully warmed-up).
I think the gauge functions correctly as there is a short delay before it climbs up when starting, and the delay is longer after an oil change.
The motor runs well, with no leaks, blow-by, or smoking, and the thermostat is working correctly. I just thought I'd throw this out there, TIA for your comments.

More important is how quickly it climbs when you tap the accelerator.

My 240D (117k miles) idles at/near 17lbs idling..... about 1/3 from bottom of guage.

It dips from full pressure, pegged at 45lbs, when shifting gears - otherwise always stays pegged while driving.

MB says the cars can idle at 7lbs. pressure without problem. My guage shakes like leaf at 15lbs after driving hard at high speeds.

Btw, this is on Mobile 1 synthetic oil..... if you are using dino oil, Harley Davidson shops carry straight 40 or 50 wt for Summer driving.

Cant think of anything that might screw up the guage, unless you've got slime deposits on the sending unit or the guage sticks behind the instrument cluster.

Sorry DieselDog, my post was strangely worded. My gauge goes all the way to the top (3 bars, or 45psi) on start-up in about 2 seconds; then the needle stays at the top under any condition (even at idle, when hot). As soon as I shut down, the needle drops to zero without delay. After an oil change the needle takes about 4 seconds to climb to the top. I use a dino 15w-40, and change it every 2,000 miles. I'm hoping this post clarifies, not clouds the situation.

I say you have nothing to worry about.... Looks like you have a healthy lower end. Every MBZ that I have ever been in woul;d peg the guage at start-up and quite a few stayed there.

If it shoot to the top and stays there, then your car is running great! :)