Pacer

I like your theory! I have also thought why people tend to get it after oil change and your description could explain it. Not sure, how the oil viscosity affects here but I'm sure you'll figure out that too
Btw, you can buy a dipstick for checking oil level manually. The place for dipstick is the red cap in the back side of the SC, on top.

Magnum20

i guess the viscosity could possibly alter the flow rate of either of the 2 parts of the pump, will have to think about that, but consensus on here is that thinner is quieter.

feeshta

One thing I have noticed is that when I was having issues with noise from the pulley bearings, the rev trick would work to quiet the engine down. Now that this has been fixed, that trick no longer works on my car. If it's whining, nothing seems to stop it except a change in temperature or driving at over around 1,500 RPM. It whined this morning, and was okay this afternoon. Temp was 1C this morning, 4 C this afternoon. Kinda weird that those three little degrees make such a difference, but it seems they do.

Magnum20

Another update, ive added another half litre of oil, the electronic level still says level ok, as it only seems able to tells us if we are either 1 litre low or 1 litre too high.
After sitting overnight i started the car today temp was 4C, after the initial fast idle period had finished about 10secs i gave the throttle a little blip and could tell straight away it seemed quieter, still has a whine but not the grinding / cavitation noise, drove off and it sounded much better than it normally does when cold, usually it sounds so horrible that i hear the noise more than the exhaust, but today it was the exhaust burble that was more prominent.
Anyway drove 2 miles parked at supermarket for an hour then when i re started the noise was back, but gave it 2 revs to 3000 and then it was gone again for the journey home. Im hoping that the increased oil level has helped and intend to add a bit more tomorrow, i have a 3rd party dipstick i can use but it isnt specific for the engine, instead of min and max marks it just has the level read in Millimeters from the bottom of the sump, so i need to find out what the measurement should be.
it’s probably all a red herring and will come back permanently knowing my luck, but got my fingers crossed that oil level is very important with regard to the scavenging pickup.
now do i stick with 5w-40 for now or go back to the official 0w-40 as its winter i think the 0 weight would be better for cold starts anyway.

Magnum20

Further update, just discovered there is a more precise oil measurement in a hidden menu, that gives an exact level in tenths of litres,
turns out even though the main display was showing level ok and then adding the extra half Litre yesterday mine is still only at 7.1 litres, the manual states 7.5L or my CLS500, so will add another 0.4 L to get it to spec. That means i was nearly a litre low even though the main display said level ok.
really hoping this turns out to be fundamental to the noise issue, could it really be this simple. Would certainly explain why a lot of us only notice the noise after an oil change, if we have all relied on the computer saying level ok instead of the exact reading.
FYI for the 55 models the capacity is even more at 8.5L.
will report back after ive tested it more.

Pacer

For the dipstick:
129-165mm level low
167-169mm level ok
171-179mm level too high

If you like, you can compare these to your figures in dash. I might do the same when have time. Right now my car is sleeping the winter away under the blanket.

E55Greasemonkey

The oil level can be checked at idle through Xentry/DAS if you have access to one. It's in the engine ECU, actual values, idle.

Pacer

Had myself activated on this at the garage today. I had 7,4L regarding the dash (55amg). I recently replaced oils and poured 8 litres per can diagram. Dash also repoeted OK. Dipstick is actually hard to read, it doesn't give exact line but there's oil all over the place. Was reading somethin like 165-167mm.
I added 0,6 liters which dash confirmed also with an OK aswell. Dipstick gave 173mm but like said, very hard to get correct value.
Gave the car a start after being sleeping for month or so. I really think it was quieter than before, normally cold start will give the grinding noise for whole raised idle period but this time it wasn't that bad. And the rest of grinding vanished after it got a little warmer (which it did earlier also though). Revving also ends the grinding noise as noticed you guys also.
I have oil pressure gauge installed and it read healthy 4 bars at raised idle and 2 bars at idle. Revving pushes it to 5,5 bars.
Oil is LM 0w-40 + moS2.

Magnum20

Using the real time exact level indicator in the hidden menu ive now filled mine to 7.5L. Although it is still noisy at startup, it seems to quieten down much faster than before, cant hear the grinding noise after couple mins of driving now.

Then decided to check the level in my dads car, i had changed his oil a month ago and had topped up until it read level ok, but now with the exact real time reading, it showed only 6.1 litres, so slowly added a little at a time until it read 7.5L, bare in mind it takes awhile to drain down so dont go crazy with it. Left overnight and it went up another tenth to 7.6L. The simple check still says level ok. So seems that simple check has a massive margin of error and really not good enough for setting the level after an oil change. So pleased ive found the much better level reading in the hidden menu.

7.5 L is the capacity for the normally aspirated m113 models, M113K models need 8.5L

its very dimple to acces, set key to position 1, select the digital speed or temp display then click the reset button quickly 3 times, you will then see an info screen showing current software version etc with the level reading at the bottom, now turn key to position 2 and it will start reading the level. It constantly reads it in real time until you turn off.

feeshta

Thank you for posting the how-to on the hidden menu. I checked it this morning, and after a little trial and error was able to find the right menu. Mine went directly to battery voltage initially and it took some fumbling around to find the correct readings.

So, mine read 7.2 liters. I added .3 liters this morning, and while I would not call the results definitive by any stretch, the car did seem noticeably quieter this morning. This was a little unusual, as it was quite cold this morning at around +1° C. Since I replaced the O-ring, it has generally made a whine that was audible inside the car at anything below around +4 C. This morning, I could only hear the whine with the window rolled down.

feeshta

Just by way of an update, my car has not produced any annoying whine in the several months since I topped off the oil levels. It's been so well behaved, I almost forgot about this issue. Now if only I could get the transmission to behave

Pacer

Nice. Mine is still in the garage sleeping the winter away but have started the engine few times just to keep things smooth and it's been very silent in terms of oil pump. Also topped mine to 8,5L based on dash.
So, maybe you should top up the transmission also Or what's the issue with it?

feeshta

Transmission likely has burned clutch packs on gears 2 and 3. Have an appointment next week to finally get it properly diagnosed. Basically it slips in gears 2 and 3, will not freewheel, and constantly holds far to high of a gear even in Sport mode.

Pacer

Got it. Smells like expensive. Get it built stronger if it needs to be opened.

feeshta

Yeah, looking into my options for a while now. It's quite expensive to have one rebuilt over here. Can buy the full transmission already built with no core deposit from the states cheaper than having your existing one repaired over here. Getting it here might be interesting though.

UncleBenz55

What part of Germany are you from? There's a garage in Oberhausen with a Mercedes Guru. He can rebuild the 722.643 to 722.649 spec (5g from the V12 models). If your engine is modified and has the torque limit removed from the TCU, that would make sense to do.

feeshta

I live near Frankfurt, which is about 2 hours 15 minutes from Oberhausen. Only modification on my car is a chip tune the previous owner installed. I don't intend to add more power, but rebuilding to higher than factory spec may still make sense. I think the guy I am taking it to for diagnosis in Frankfurt could do the same if asked, but will talk to him more next week.

UncleBenz55

That's neat, i'm between Bonn and Koblenz, about 80mins from Frankfurt, so not too far away

feeshta

I've been up through that way a few times. Our German counterparts office was in Rheinbach until very recently and we have traveled up there for meetings a few times. Not exactly sure where they just moved to, but I believe it's somewhere in that area so I will be back I am sure.