Way back in my late teens when i first had cars, I thought thicker = better protection but now I disagree. Oil pumps have pressure release valves that vent excess oil once a particular pressure at the oil pump has been reached. In addition to this, thinner oil simply flows more through the same restrictions. Thinner oil flows a lot faster through the engine and far more oil ends up going through the engine instead of straight out of the relief valve, providing better oil flow and cooling. Also thinner oil travels much faster on cold starts. I run 0w-40 in all of my cars. At the very most, I would maybe consider 5w-50 for track work in hot climates.

I can't recall specific details, but folks on this forum, ones who've been around these cars for a while, collectively agree that sticking with 5W or 0W-30 oil is best. I respect Tasos, but I concluded that I'm going to stick with what's been agreed here by folks who've driven these cars for years with no problems. If I recall correctly, the lower viscosity oils will strain the engine, no bueno. As we discussed here, and other threads have too, using liqui moly etc. is the go-to for coating internals to reduce friction and wear.

30w is not sufficient when hot IMO. MB went out of their way to specifically mention in their oil charts not to use it on M156/M159. Just go 0w-40 (my preference) or 5w-40 and you're good to go!

I meant 40 haha, thanks! 30 was what I used on my old e36 M3, RIP.

Actually the correct MB spec is 229.5 and that includes some 0w30 oils..

https://bevo.mercedes-benz.com/bevolisten/229.5_en.html

But the general consensus is 0w30 is too thin for our engines and MB used to use 0w40 M1 and now use 5w40 M1 to try and mitigate lifter bleed down problems with the M156.

There are some really good threads on this topic and awesome (detailed) posts by some of the more experienced members..i luv reading this stuff ..links below.

https://mbworld.org/forums/c63-amg-w...0w40-5w40.html
https://mbworld.org/forums/c63-amg-w...c-229-5-a.html
https://mbworld.org/forums/c63-amg-w...-question.html

https://bevo.mercedes-benz.com/d/d/en/Spec_223_2.pdf

Note the number 2 next to the 229.5 dot for some engines including M156.

Point 2 at the bottom of the page reads:

Restriction: Only SAE 0W-40 und SAE 5W-40 engine oils are allowed !

Good Find

Update: MB did not agree that my cams and buckets needed replaced and consider the wear normal (maybe normal on an M156 but I would not consider it normal personally). They did however decide the cam adjusters where a bit noisy and where the cold startup so they replaced those for me at their expense, so at least i got that out of the deal and will monitor cam wear and maybe do cams and buckets at some point.

The problem is that the intake camshaft is higher than the exhaust. Thats why the echaust camshaft is mostly in good shape and the intake done.
I‘m not a engineer but it shouldnt be a rocket science to solve this problem.

That is generally the issue, the exhaust cam is better oiled, although if you look at my pictures on the first post you will see both cams have the same equal wear on my car (one cam has yellow paint and one has blue) and the exhaust cam is wearing as much oddly.

It’s the metallurgy in the cams. Not hardened and in some cases pitted /cavatations within the metal. No amount of oiling is going to save that.

Let me correct you with something, I used many brand of oils Mobil1, liqui moly, motul, AmsOil, and Redline in my 09 c63. With Mobil1 temps with always stay high, and I got two times a lifter stuck,well I switched to Liqui moly after the amazing reviews after 3k oil change intervals, better cooling of the oil, but lifter got stock again but only ones,, next 3k oil change switch to Amsoil now with ceratec and a zinc additive, no more lifter stock. Next oil change at 3k Motul with Liquimoly hydraulic lifter additive and Mos2 additive, and the car runs like a tesla. So freaking quiet and smooth and temps where always stable because of the ster base oil motul uses. Next Redline same as motul with the difference that I had to add two quarts of oil in a period of 4k oil change intervals and oil was not cheap I spend 125$ for for 12 quarts of oil.. now I am happy back with motul for ever

I have been happy with Motul in other cars, have not tried it in the benz yet - which one did you use 8100 x-cess which is 229.5 approved?

Go with molygen 5w40 and a can of lifter additive from them. I use molygen and 8100 and I just went back to molygen from 8100 and the car sounds 10x better.

Yes sir..

Thanks, I have a can of lifter additive in it right now with MB oil, next change was thinking about liquid moly have been happy with it in everything else I run it in.