Where does your oil pressure gage sit at idle?
Thread Starter
Super Member
Joined: Feb 2008
Posts: 844
Likes: 1
From: Orland Park, Illinois
1994 E320 (current)
Where does your oil pressure gage sit at idle?
My oil pressure gage is pinned at the top from the time I turn on the car. Just curious as to where some of yours sit while running. I don't know if it is normal or I need to replace the pressure sensor.
Thanks
Thanks
Senior Member
Joined: Nov 2004
Posts: 457
Likes: 0
From: Lockport, IL
'95 3.2 M104
according to mb of westmont op sensors are going bad alot and sometimes i can read "0" after 20mins warm up. ...but as long it shows pressure after accelerating....your good. you can also test if it works... and here is how to do it.
Turn key in steering lock to position 2 (battery voltage).
Unplug electrical connection from oil pressure gauge sensor (B5). Specified reading: 3 bar.
If specified reading is not achieved: test cable from oil pressure gauge sensor (B5) to instrument for short to ground.
Cable in order: replace instrument.
With engine off, oil pressure gauge rises. Connect cable from oil pressure gauge sensor (B5) to ground. If reading is 0 bar, replace oil pressure gauge sensor (B5).
If reading remains at 3 bar cable has open circuit.
Note: The oil pressure gauge is controlled electrically. The oil pressure gauge sensor (B5) installed in the oil filter attachment controls the gauge in the instrument cluster. There will be a positive reading at the oil pressure gauge in the instrument cluster when the ignition is switched on. Negative is applied to the oil pressure gauge through the sensor (B5). As the pressure rises, the ohmic resistance of the oil pressure gauge sensor (B5) increases and the reading of the gauge alters.
Oil Pressure Sending Unit
Pressure (bar) Resistance (ohm)
0 approx. 10
1 approx. 69
2 approx. 129
3 approx. 184
Resistance values of pressure transmitter in dependance of prevailing pressure.
Turn key in steering lock to position 2 (battery voltage).
Unplug electrical connection from oil pressure gauge sensor (B5). Specified reading: 3 bar.
If specified reading is not achieved: test cable from oil pressure gauge sensor (B5) to instrument for short to ground.
Cable in order: replace instrument.
With engine off, oil pressure gauge rises. Connect cable from oil pressure gauge sensor (B5) to ground. If reading is 0 bar, replace oil pressure gauge sensor (B5).
If reading remains at 3 bar cable has open circuit.
Note: The oil pressure gauge is controlled electrically. The oil pressure gauge sensor (B5) installed in the oil filter attachment controls the gauge in the instrument cluster. There will be a positive reading at the oil pressure gauge in the instrument cluster when the ignition is switched on. Negative is applied to the oil pressure gauge through the sensor (B5). As the pressure rises, the ohmic resistance of the oil pressure gauge sensor (B5) increases and the reading of the gauge alters.
Oil Pressure Sending Unit
Pressure (bar) Resistance (ohm)
0 approx. 10
1 approx. 69
2 approx. 129
3 approx. 184
Resistance values of pressure transmitter in dependance of prevailing pressure.
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
Likes: 1
From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
It will stay pinned at the top until the oil warms up, then it will be lower at idle. The warmer the oil, the lower the pressure at idle. If it is very cold outside it could take a long drive to get the oil warm.
Anything above 0 at idle is OK.
Anything above 0 at idle is OK.
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Thread Starter
Super Member
Joined: Feb 2008
Posts: 844
Likes: 1
From: Orland Park, Illinois
1994 E320 (current)
Oil pressure gage
guess the Benzkopf's in Germany wern't to concerned about oil pressure unless there was none. So the gage isn't very gear-head friendly, I guess I am just used to watching that thing as a tool for engine health. I'll get over it....Or I could get one of those really cool sport compact tuner gages and slap it on my dashhboard next to the coffee can sized tach (cause if isn't that big it apparently it won't work right) that way I can see it with my neons on. 
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
Likes: 1
From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
guess the Benzkopf's in Germany wern't to concerned about oil pressure unless there was none. So the gage isn't very gear-head friendly, I guess I am just used to watching that thing as a tool for engine health. I'll get over it....Or I could get one of those really cool sport compact tuner gages and slap it on my dashhboard next to the coffee can sized tach (cause if isn't that big it apparently it won't work right) that way I can see it with my neons on.
on us! 
It's not that bad. Just multiply the reading by 14.7 to convert to PSI, which makes a little more sense to us silly Americans.
