I just bought a 93 300e 2.3liter, the oil pressure guage sits on zero at idle, then at acceleration it climbs. Is this normal for this car? There is no lifter noise or anything out of the ordinary, other than the guage.

Replaced a bad sending unit last week for the same exact symptom. The part is pretty cheap, and certainly less money than paying for an oil pressure test.

will it hurt to drive the car like this?

If the oil pressure is really zero at idle, yes it will hurt it a lot.

Check with a mechanical gauge to verify if the problem is a gauge inaccuracy or the engine. More often than not, the problem is the gauge, and the problem is the sending unit.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record

Thanks for the help. This is a great forum!

Mine is nearly at " O " as well too when idling in drive,*IF* the engine temperature is around 85-88*C - which is the highest I have ever seen it, but by 1500 RPMs- it is back to "3", which I heard was normal. When around 80*C, which is where it is usually at- the oil needle is around .5 .

When idling in park when the engine is fully warm @ around 85*C, it is around the "1" to "1.3".

I am hoping a new oil change and a MB filter will increase my oil pressure, but perhaps my sending unit is in need of replacement as well - or the engine. I do not even care anymore.

Min allowable oil pressure at idle is .7 bar. Using a higher viscosity oil in the warm weather will bring the oil pressure up a little.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record

When I got the car I ran 20w50, and the oil guage was more responsive. I recently had the oil changed and they used 30w, and every since its less responsive. I guess I should request 50w at the next oil change.

Unless I missed something, the correct engine designation would be 3.2L, not 2.3...and for future reference in this forum, you have the M104 engine.

The sender switchout would be your cure. This is a half-hour job with a cresent wrench. It's a bit tight down there so use a short one...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

When in doubt, I hear the users manual has some useful stuff to say about oil viscosity, seasons and so forth...


cheers,
dan r.

You're right. I have a 3.2 liter. Thanks for the bit of info on the sender switch. Thats sounds like a good job for the weekend!!

This is the first MB I've owned, is there any other problems I should look for at 200,000 miles?

Hmm. It must vary from model to model. In the owners manual for the W126 (gasoline engine) it states that the minimun oil pressure is .3 bar.

I changed my oil to my usual 20w50, my oil guage is more responsive like it was when I got the car, but it still drops when the accelerator is released. I think I will replace my sending unit next. I don't have any lifter chatter or altered performance. Thanks for the tips!!

Shouldn't drop to zero...ever!!! Unless it's not running or your oil pump goes south!

Sender should cure the problem...

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car