w124 OM606 N/A Oil Pressure - PeachParts Mercedes-Benz Forum

thatguy · #1 12-20-2011, 07:18 PM

My 95 E300D oil pressure gauge likes to read 3 all the time, even at hot idle. I know this is a symptom of a faulty sender, but I am not getting 3 bars with just the key on, it only goes up after the engine is running. When I turn the key but keep the engine off it doesn't change at all, does this still sound like a bad sender? If so, where is it on this engine? It's kinda crowded down below the filter housing, is it still in that same location?

BTW my idle is about 700rpm so it's not a high idle problem. Oil is 15w40 dino Lubro Moly, fresh oil as of yesterday.

Thanks a ton, this car is kind of new territory to me, I've been a die-hard 617 guy for years though.

engatwork · #2 12-20-2011, 07:46 PM

IIRC it is in the vicinity of the oil filter housing. May have to look up at the housing area towards the back from underneath? Again, going from memory here. I've had to replace the sensor on the silver E300.

thatguy · #3 12-20-2011, 08:31 PM

Thanks I'll definitely have to give it a look. The puzzling part to me is the fact it remains pegged at hot idle, but doesn't exhibit the textbook sender failure symptom of being pegged when the key is on but engine not running. Is it possible my engine really does run that well? It has impeccable maintenance records from day one with Delo 400 changes 3k religiously, virtually zero blow by and very easy cold starts with plenty of pep through the RPM range. Even after driving two days on my new oil it remains nearly clear looking on the dipstick, whereas my 617 blackens it up almost instantly after a change.

engatwork · #4 12-20-2011, 08:34 PM

IIRC I don't get any reading without the engine running either.

thatguy · #5 12-20-2011, 08:42 PM

Quote:

Originally Posted by engatwork

IIRC I don't get any reading without the engine running either.

Interesting, I had one kick off in my 617 a few years back and it would peg with the key on but engine off, perhaps the 606 is a little different in that respect. Either way, it's a cheap part and I think I'll replace it, it did appear to be working a few weeks back when I got the car, but even then it was pretty high at hot idle, just not 3 bars.

Thanks again

benedict · #6 12-20-2011, 09:07 PM

Mine won't show anything until started either.

It will read 3 bars until nice and hot, once hot 80-90C on the temp guage, it will fluctuate around 2 bars but go back to 3 bars around 1200rpm.

I'm running a 5W 40 full synthetic but when I run a Dino oil it does tend to stay around the 3 bars. In theory it shouldn't matter as the viscosity of the two are the same when hot but for some reason synthetics seem thinner.

What is the reading on your temp guage when warmed up?

foolio · #7 12-21-2011, 12:49 AM

Overfill your oil by accident? An extra qt. can keep it pegged.

thatguy · #8 12-21-2011, 01:06 AM

Quote:

Originally Posted by foolio

Overfill your oil by accident? An extra qt. can keep it pegged.

I checked and it is a few mm below the top red notch, so oil level is a-ok.

barry123400 · #9 12-21-2011, 01:24 AM

Maybe the sendor maybe not. The only way to tell easily is to change it. If something is questionable the sender is the most likely suspect.

Your mercedes is newer than a lot of members and the temperature gauge is operating well .There is no past mention of an instrument voltage regulator in the dash. Even if there was one it is not bad. Or the temperature would be reading abnormally as well.