^ Maybe I'm confusing things with the C300 requirement. That's good news!

 

It is the same MB Spec sheet 229.5 for all C Class with the restriction: Only SAE 0W-40 /SAE 5W-40 engine oils may be used in the C 63 AMG. (2010 Operator's Manual). I think the preferred viscosity may have been updated since then to SAE 5W-40 for the C 63 and MB Spec 229.51 now being allowed as well.

 

The MB 229.51 spec is mainly different from the 229.5 spec in that it is a low ash oil composition that is required by the fine particulate filters on the newer MB diesel engines. It meets all of the other 229.5 standards, and MB is now also using it for their gasoline engines. Unlike the diesels, the gasoline engines do not require 229.51 and are fine with 229.5 spec oils.

The viscosity of the oil is a different subject, and every single AMG engine that I know of requires a 40-weight oil (SAE ?W-40) as the 30-weight is too thin to provide adequate protection at high stress/load and operating temperatures of the AMG engines. The cold viscosity (0W or 5W) is achieved by the addition of viscosity modifiers to the base stock so that it flows more easily at low temperatures.


Engine Type MB Approval Number Approved Oil Viscosity Range
113 229.5 0W-30, 0W-40, 5W-30, 5W-40
155 SLR 229.3 5W-50
156 229.5* or 229.51 0W-40, 5W-40
272 229.5 0W-30, 0W-40, 5W-30, 5W-40
273 229.5 0W-30, 0W-40, 5W-30, 5W-40
275 229.5 0W-30, 0W-40, 5W-30, 5W-40
642 229.51 0W-30, 0W-40, 5W-30, 5W-40
*156 engine using 229.5 should use only SAE 0W-40 oil

The interesting thing to note is the footnote for the M156 engine, which leads me to believe that there may be some other differences between the 229.5 and 229.51 oils, namely that the 229.51 oils flow more easily at low temperatures than the 229.5 oils of the same viscosity. Hence, MB started using the 5W40, MB 229.51 spec oil - made for them by Exxon as Mobil 1 Formula M ESP 5W40 - as standard fill for the M156 engine cars.

So, the C63 with its M156 engine requires 0W40 oil that meets the MB 229.5 standard, *OR* 5W40 oil that meets MB 229.51, which is now the factory fill (Mobil 1 Formula M ESP 5W40). As this oil is only available through the MB dealerships, the obvious choice for those not servicing their cars at the dealer is Mobil 1 0W40, while the dealer will use Mobil 1 Formula M ESP 5W40.

 

Table didn't paste properly - here is the actual screen capture.