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500 DXB
10-09-2011, 01:13 PM
General oil pressure query.

When my 1993 E500 is warm (say 90f) oil pressure needle sits up at 3 bar at 2,400rpm at 115kmh - this is worrying as previously would sit about 2.1 bar. At idle (600rpm) the needle sits at about 0.9 bar.

Any ideas of what it should sit and is there a sinister.

In general car is running perfect and oil level is good and clear.

Any feedback greatly received.

10-09-2011, 02:15 PM

As far as I can see your sender is working OK

At those RPM I would expect 3 Bar.

Also at Idle you are low, but not in crisis.

The following text is based on searching this site (GSXR?) and perhaps other sources.

If the gauge reading is full scale as soon as you turn on the ignition check the wiring and the oil pressure sender.

An open circuit from the sensor to the gauge due to a broken wire or bad connector will send the gauge to Full scale..

A bad oil pressure sender will do the same.

To test:

Unplug the wire from the pressure sender and touch it to ground. If the gauge comes down from full scale then the wiring is OK but the sender is bad. This was my finding.

If the gauge remains at full scale it is a wiring problem: look for a break in the wire or a bad wire-to-sender connector. The sender in this case is probably good.

Having recently replaced my sender (Ebay 32 GBP) I am pleased to see 3 bar all the time except when idling at 44 degees C in a traffic jam when I see 2.5 bar.

500 DXB
10-09-2011, 02:26 PM
Thanks for this Jim hope all is well in Muscat and you are enjoying the cooler weather down there. Things still hot in DXB.
Quick question the 722.370 Gearbox, 2.65 Differential you have would you recommend them? Also you ever get the AMG back muffler sold? cheers

500 DXB
10-09-2011, 02:44 PM
2.5 idle at 50c I have never once seen and the needle drops straight away when I come off the throttle, shoots up to 3 bar when on light load and pins itself there under heavy/full throttle. So think it is all good? I do have low back pressure back muffler on the car would this affect oil pressure at all?

10-09-2011, 03:27 PM

Please see Performance Mods regarding Gearbox and Diff.

The Low Back Pressure Back Muffler will not affect oil pressure.