Vash

I hope he doesn't mind me quoting him, but this is Steve from Weistec in regards to the 0w40 vs 5w40;

"Issue 1: These engines take 0w-40 synthetic oil from the factory. If you have the dealership change your oil they put 5w-40 synthetic oil. Although MB isn't admitting any type of guilt here, they have obviously learned to change the oil. The reason for this is because the lifters are known to bleed the oil out when the camshaft is in the correct position overnight or for a few days pressing against the lifter. When someone starts the car the next day you get the lifter tick which many people have complained about. If this happens enough times, it will cause an issue, and this can perhaps be the reasoning behind this."

"Lastly, just an FYI for guys running the M156/M159 engine. If you haven't driven the car in a few days and you hear an kind of valve train noise, do not drive the car. Let it idle till the noise goes away. Also put 5w-40 in the engine if you haven't yet. Thanks.

Steve
Weistec Engineering"

from another Benz site

Just confirms what I was saying (regarding lifter "tick"). Apparently this can lead to serious issues.

Ingenieur

My dealer oil change last month used 0w40
5 dealer changes to date
First 3 used 5w40
Last 2 used 0w40
Both are similar when hot so should drain the same ?
Obviously the 5 is thicker when cold
An arguement could be made for either to improve lifter performance
The 5 is thicker so drains slower but when hot they are the same?
The 0 is thinner so will pump them up faster
Really no difference

Vash

I would agree, however, after a dealer oil change (they used 0w40) I started getting the lifter noise. Checked the oil level, looked good. I wanted to see if anyone else had experienced the "tick" and found that many had and that 5w40 was the cure (per this site and others). Called the dealer and asked what they had put in, swapped to 5w40, no more lifter noise.

Using 5w40 ensures that I'm not accruing any unnecessary wear, where 0w40 would have been the cause.

Even Weistec recognizes that 0w40 can potentially cause a problem. Who's going to argue against MB engineers and Weistec?

Ingenieur

There is no lubrication difference 5w40 vs 0w40
If the esp version is used the 0 may be better
MB 229.5 mobil 1
0w40 approved
5w40 non esp approved, I will confirm what the dealer uses
5w40 ESP NOT approved, it is 229.51 approved but the us m156 requires 229.5

In reality no difference
My car has never ticked, even after as long as 10 days and has been 0w40 since before I owned it
Oil makes no difference
Only time
And cam position, ie, if it leaves the fill port exposed

whoover

Good summary. But for people who would like to make a fully informed decision, I remind them that Bevo/Butthead omits the fact that all late-model C63 maintenance manuals from MBUSA call 229.51 approved:
http://www.mbusa.com/vcm/MB/DigitalA...ce_Booklet.pdf

Page 8.

If you too are from a planet where the book in your glove compartment doesn't count, avoid the ESP oil. Otherwise, feel free to join us.

jcfay

Not that I want to throw my gloves in the ring here, but I'd tend to not trust the glovebox manual over time for some stuff, especially items that the manufacturer could upgrade and refine their judgment on over time (like engine oil). That being said, you guys obviously know WAY more about oil than me. Personally, I think I ended up with 5W40.