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the noises usually occur when the car sits longer than 5-6 hours in cold( below 5-10 Celsius) even on a plain surface;
If the car stays in the sun I do not remember hearing the above noises;
the noises usually occur if the car is on an inclined surface with the "nose" up;
the noises occur only at the first start and never come back even if I stop the engine right after I started it;
the oil is always at 5.5-5.4/5.5 liters. The battery is always at 12.4-12.5V.
I tried 5W/40 and 5W/30 all with MB approval for this engine, but no improvement;
Due to this issue described above I decided to change the timing chain, tensioner, slides, and the sprockets(full sprockets not only the teeth) about two weeks ago. The operation was successful and I've made 1500km till now even at max speed(200+km/h) for a couple of minutes, with no check engine, no power loss, and no strange noises while running. The car continues to do the above noises and for example, in the last week, it happened...3-4 times / 7 days. Is like an improvement...unfortunately in the bad direction.
I thought it could be the: 1. the Bendix from the electromotive - I'm not that sure about it; 2. Oil pump, maybe the oil pressure is low at the beginning and the chain tensioner is not fully stretching the timing chain; 3. vacuum pump - I saw something on some MB forums.
4. Camshaft adjustment screw/valve A2710500171, picture attached Especially the one from the left side because as I remember the original sprocket from the left side had some nasty wearing there and maybe is something wrong with this "SCREW" or whatever is called...
This is what I've changed to the engine:
I need to mention the fact the car at this moment is in service, the indie decided to keep it there for 2-3 days to listen it in the morning and do some testing.
Update: I took the car today from the service, they told me that the sound didn't occur during the testings but they decided to clean the solenoids(took them out, clean them, etc.) the guy seems to know about how this engine works, he explained me a little bit how these magnets are moving the entire assembly of the camshaft adjuster. I noticed that the engine seems to be more quite at an warm start, I'll test the cold start in this evening and I'll also come back with an update after 4-5 days.
Selenoids are the two round magnets that are in the front of the engine each of them has a cable attached connected to ECU.
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