The Oil Pressure in my 84 380 SE fluctuates betweeen 1.5 and 2 bar while idling.

Normally, the idle pressure is 1.5 bar. Once in a while it may sit at 2 bar while idling. However, the needle is always flickering at 1.5 bar. Never steady.

Is this a matter to be concerned about ? What should I check / replace ?

You may want to verify this phenomenon with a good oil pressure gauge. It may be simply a bad sending unit that needs replacing.

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95 E320 Cabriolet, 159K

I don't know for sure.... but I think what he's experiencing is normal. I have a w126 and it does that too.

It's often leaks in your intake manifold which dominate the air-fuel mixture at idle (not at speed) and cause the engine to rev up and down - too little to see on the tach, but detectable on the oil pressure gauge and by ear.

As me how I know.

An excellent way of detecting leaks is to take the car to your indy and have him pump inert white gas into the engine - intake leaks are pinpointed with this technique.

I second Thomaspin.

Vacuum leaks have very significant effects. It would not take much to rev the engine irregurlarly.

The idle oil pressure is far more than enough, don't worry about that ....but do check all your tiny and hard to inspect hoses.

Mark Shinnick
www.mastertimer.com