I generally dislike Castrol because of their misleading advertising of Syntec. They claim it's "synthetic", when actually it is mostly Group III base stock (hydrocracked dino). Mobil sued over that, IIRC, but they lost and Castrol was allowed to continue calling it "synthetic". At least one person who has a fleet of MB diesels used SynTec for a while, and noticed the oil consumption increased measureably at about 5kmi, along with the return of valvetrain noise. Changing to fresh SynTec cured it. He then switched to Mobil "true" synthetics, which easily go 10-15kmi with no increased consumption or noise. Penzoil has a bad rap about sludge from years ago, but their current stuff may be better.
It boils down to the fact that the two BEST diesel oils on the market are Delvac-1300, and Delo-400. Both are easily available at most McPart places (AutoZone, Kragen/Shucks/Checker, WalMart, etc) for about $7/gallon. They blow away pretty much any other diesel oil in performance. For synthetics, Mobil makes an excellent product, as does RedLine and Amsoil (the latter two being more expensive & harder to find). I like Mobil Delvac-1, which is a super-duty diesel version of Mobil-1, but Delvac-1 is HARD to locate! It's agruably the best stuff on the market for diesels, period. I have been changing at 10k and getting oil analysis, and so far, it apperas I could easily go 20kmi between changes easily. Some folks on the MBZ lists are going 15-20kmi on Mobil synthetics with clean oil analysis results.
You are right, oil preference is highly subjective and a personal preference. I base my choice on Mobil's excellent track record, reasonable price, and ease of purchase. If cost were no object, I would probably use RedLine products, which contain more Group V (ester) base stock, and therefore cost a lot more ($8-$10/quart!)... although the benefits in normal street driving are probably nil...
HTH,
07-08-2003, 11:40 PM
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