My dealer uses Rotella T 15w40 in all the non-synthetic-requiring cars, which I am assuming would be all the pre-98s. Mine is a 97 c230. I picked up a case of 6 gallons for $35 and some filters, so that I can have the dealer use this while the car is still under Starmark warranty. Question is, is this ok for the colder months, or should I look for something in the 5-10w range?

I will likely convert to Mobil1 5 or 10w40 after the warranty period, when I'm not paying labor for oil changes.

Will, why wait until the Starmark Warranty runs out to switch to Mobil 1? Start using it immediately. If you're in NC 15W40 oil should be fine for year round use. Check the oil weight vs. outdoor temperature chart in your Owner's Manual to confirm that it's OK. Realize that the dealer isn't going to service customers' cars with an oil that will cause problems during the winter months.

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Fred Hoelzle

I like Mobil1 and have used various grades in other cars, but this is large 4cyl with a 7qt capacity that gets changed every 5k, and never sees over 3000RPM on 99% of occasions. So.......

I was under the impression that Rotella T is godd stuff as far as gas engines go. (SJ/SL rated)

Here you go: http://www.whnet.com/4x4/oil.html
All your questions answered.

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2007 C 230 Sport.

I've seen that site, but it lists Rotella T as MB-certified for 228.3 - which pertains to diesel, not gas, which for me would be the 229.1 or earlier. 229.3(SJ) or 229.5 (SL), are both met by Rotella T, though no mention of Rotella T by Mercedes as "approved for 229.3/5?"