MI MB dealer used 10W30 Valvoline oil, and TN dealer used 15W40 Mobile.
Someone from CA posted 20W50 Castrol. Appears than MB does not recommend any specific grade/brand or the MB dealers do not follow MB directions. SAE certification is probably the most important thing for oil.
The chart in my owner's manual and Alldata are a little different, but the MB chart in ALLdata has everything from 0w to 50w, so MB recommendations are wide open. Grades like 20W50 are not recommended in colder climates.
The recent problem with the FSS and MB increasing the warranty period to 150,000 miles, does not make the best case for following MB recommendations to the letter, even if their recommendation were not this wide.
On the other hand, GM makes a whole lot more cars than MB and they have plenty of engineers. They recommend only using 5W30 all year, all climates and give 10W30 as an alternate, only in warmer weather. Specifically recommend against using any other grade like 20W50.
Again, grades like 20W50 do not do much, as most of the engine wear occurs at start up, and something like 0W or 5W is going to give you more protection there. Once the engine is fully warmed up, all oil grades work fine.
Conventional oils with a wide range have a lot of polymers, which are a concern. This is not a problem with the synthetics.
Please post any experiences where using 5W30 has affected the engine adversely.
94 E320 58000 Miles
Last edited by zafarhayatkhan; 06-09-2003 at 11:08 AM.