My 93 300E oil pressure gauge stays at 0 at idle and only goes up when driving??? what are the possible problems, if any?? The oil level is normal.

Does the oil pressure gauge stay a 0 when you turn the ignition on? Then when you start it like when it's cold does it go all the way to the 3rd bar? When you are driving it does it go to the 3 bar ... like at 30 mph at least?

when i start the car the gauge goes up to top level and then after a few minutes slowly drops to 0 and stays there unless i give it gas or am driving, at a redlight it drops back down to 0.

What oil are you using?

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

10-40 oil

How many miles are on the 300E?

I was wondering how long has it been happening? Did it possibly start shortly after changing oil & filter. This is an occurrence, that seems to happen on them. I have read quite a few reports on this happening. Usually, the suggestion is the sender unit, but I don't think that is the problem. There has been mention of the oil filter causing the issue. What kind of filter do you normally use? As of yet I haven't read of anyone replying with the fix on any particular one.

Most likely the sending unit. Mine just went out recently, 1991 300CE 180M.

I use the MANN filter on my oil changes, is there a way to test the sending unit?

Sending units are cheap, hardly worth testing. Inspect your lower harness too, common failure. But consistent behavior / low readings sounds like bad sending unit. It's easy replace, accessed from below.

Testing the sending unit...1bar=40ohms, 2bars=90ohms, 3 bars=750ohms or more!

When unplugged from sending unit the OPG should max out, and you should be able to grd. it out. That will prove the gauge is good.

If all this pans out, you probably have a wiring issue of some sort.

On mine it was/is the lower wiring harness. I decided to live with it.

On my next oil change, in getting the filter out I casually pulled the wires back, replaced the filter, etc.

Works like it should ever since. Until the next oil change probably, but I'll take it.

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1993 300E
1999 E320 Estate

same here. Living with it like nothing wrong. But will change once i get it from jy.

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1) '04 S500 Gold/Beige......120k Miles
2) '93 300E 2.8...Green/Tan MBTex..........202k Miles(and going)
3) '89 420SEL...Light Blue/gray Leather....155k Miles (Retired )