Your statement is not universally true. The owners manuals in many cars made in the last 10-12 years state that oil should be checked on a fully warmed up engine 3-5 mins. after shutting it off.

The "let it sit over-night" or "wait an hour or so" concept no longer applies in all cases.

One has to follow the instructions given in the mfg-provided owners manual.

I would love to see scientific evidence that synthetic oil of a given viscosity takes longer to drain down than it's conventional counterpart.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

This is exactly what the owner's manual says for my '96.

Im sorry im a newbie how do I check the oil pressure?

The car has an Oil Level Indicator on the dash..did that show low oil ??
If NO , you are OK and it just needs topping
Your original post stated they Forgot to put in the oil. That did not happen .

Is there not an oil pressure gauge in the instrument cluster in front of the steering wheel?

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2012 E350
2006 Callaway SC560

Well, I'm amazed. It appears there is no oil pressure gauge in that instrument cluster.

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2012 E350
2006 Callaway SC560

Oil Level Indicator...so, if they forgot to add the oil , they would certainly have seen the Warning indicator..even if it was just low.. they may also have just gone by the indicator instead of the dip-stick.
Should be fine and use the Dip Stick ..1/2 way mark is fine at 20C

There sure isn't. That was deleted.

There's nothing wrong with checking your oil after sitting overnight, especially if you don't consider the "Min" mark to be a good place to leave it. You're less likely to overfill it that way.

With the gas versions of this era you can check the oil level from the dash and the display will tell you if OK or 1 or 2 qts low, etc.

The E300's of the same years do not have that feature; they only display the low oil level warning.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

I'm going to keep checking my oil after it sits overnight, when most of the oil is in the pan and I can really see how much oil is there.

I can tell you this...the oil will wick up the dipstick so you should wipe it off, reinsert it, withdraw and read it. I especially see this on aircraft engines where the oil is generally thicker than what cars use.

And for the original poster of this thread, diesel engines are noisy and the oil pressure gauge is the gold standard for verifying that oil is being circulated thru the engine, not the dip stick.

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2012 E350
2006 Callaway SC560