I am thinking of installing a Oil Pressure Gauge in
my 83 240. Which gauge would be better a 3 bar or 5 bar?
I know the sender is different for each of them.
When I go to install the oil pressure sender unit will motor oil leak
out of the engine when I remove the present oil light switch?

Thanks,
Joseph in The New Mexico

How about a VDO 80 psi gauge and sending unit. Much easier to get and uses the same sending units.

Regards,

Paul

I just changed my oil pressure sender (on a B230F, not your B23F, but I don't think it makes any difference) -- I waited a few hours before unscrewing it and it didn't drip at all.

I would go with the 5-bar so that the gauge doesn't "peg" and you can get a more accurate reading at speed.

It's funny though -- I had a few M-B cars back in the '80's and early '90's, and they all had 3-bar scaled oil pressure gauges (not anymore), and it seemed that the company was more concerned about idle pressure than pressure at running speeds. It was considered normal (in fact, it was stated as such in all their owners manuals) that the pressure gauge should peg as soon as engine rpm rose above ~1K. But they had a warning (see your dealer if ...) that the reading at idle shouldn't drop below 0.5 bar. I guess it's a difference in pressure priorities, MB being more concerned about an accurate reading at idle than at speed.

Half a bar, about 7 psi, seems low to me, but I'm not a Mercedes engineer. And I used synthetic oil on those (and all my current cars), though, and I never saw an idle pressure below 1 bar, which I was happy about.

"When I go to install the oil pressure sender unit will motor oil leak
out of the engine when I remove the present oil light switch?"

Not much. (unless you do this with the engine running....)
Have the other fitting ready and a few paper towels to wipe up what little does spill (if any)
--
George Downs Bartlesville, Oklahoma

5 Bar. Volvo changed to the 5-Bar in later models that had the gauge package, probably because at normal operating pressures other than when idling, the 3-Bar gauge was always pegged at max.

Multiply "Bars" by ~14.7 to convert to psi. 3-Bars is about 44psi and at normal driving RPM's the engine typically has more than 50psi oil pressure.
--
Bob: son's XC70, dtr's '94-940, my 81GL, 83-DL, 89-745(V8) and 98-S90. Also 77-MGB and some old motorcycles.