Ya'll need to call 1-800-FOR-MERC and request the lastest and greatest "MB Approved Service Products List". Its free and they'll deliver it UPS to your door. The copy I have lists 6-7 approved oils for use with FSS systems - ALL are synthetic, including Mobil 1 15w-50 and 0w-40, Castrol 5w-50, and some other brands only readily available in Europe. The same document says the listed viscosity chart supercedes "ALL" other viscosity charts. It specifies that 229.1, 229.3, 229.5 be used, when they are not available then B3/B4 and as a last resort CH-4 (these are the diesel specs). Now, for older Mercedes is says that conventional oils MAY be used. The lastest edition has a longer list of approved synthetics.

The other issue is that for FSS vehicles before 2000, MB did NOT require synthetic oil for the FSS system. Starting in 2000, they did. So, for some engines the warranty has been extended to 150Kmi. This is particularly important for FSS vehicles 1998-2000.

The extended warranty information may not be applicable to those outside the U.S. The approved service products list MAY be different outside the U.S. as well.

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Brian Toscano