Oil gauge

[Mr. Smoothy]

I have a 88 420 SEL. the oil gauge goes to 3 when car is running. is that normal or should it go up and down as the engine speed increases and decreases?

[sixto]

3 when you're driving. Hopefully no lower than 1 when idiling.

Sixto
91 300SE
87 300SDL
83 300SD

[Mr. Smoothy]

It stays on 3 all the time. except when engine is off.

[sixto]

If it's not on 3 when you turn the key to on before starting the engine then you're in good shape. If it goes to 3 before the engine's turning, something's not right.

It's not uncommon to see MB engines idle at 3 at operating temperature but it's more common (I think) to see it dip a little.

Sixto
91 300SE
87 300SDL
83 300SD

[daddiojiggy]

funny,but just recently my guage started going to about 1 unless i was using the throttle and then it would close to 3.as far as i can recall it was always at 3 while running but just the other day -after idling for about an hour -i got back in and noticed it was idling around 1 and only at 3 while under power.could i have done something wrong by idling or is my oil sender just about to give it up?

[sixto]

I use the oil pressure gauge as something of a FSS on the 300SE. When the oil pressure gets close to 1 at hot idle, it's time for me to change the oil.

Sixto
91 300SE
87 300SDL
83 300SD

My car idles around 2.5 after being warmed up.

Goes to 3 with throttle.

Before I did an oil change (10,000km) 2 months ago, the idle was at 2 so i guess you can treat the oil pressure gauge as a FSS.

But never seen my oil pressure go any less than 2.

Maybe it's different for different cars???

Who knows...

When started cold, it idles at 3.

My $0.02...

[G-Benz]

If it goes to three when you just turn the key to the "on" position, then you have a bad oil pressure sender...