I have used SYN's in my gas burners but not in my diesels. I have found a VERY good dino oil I like for my MB diesels. BRAD PENN.
Hard to find though. Only find it at small distributers in Atlanta area. It has all MB ratings I guess it is for it's big truck line but when I put it in my 300K SD I add no oil in a 4000 mile change. Unlike other brands. Rotela is the worst for burnning it like fuel.
Goood luck oil is a bad subject here i have never replyed on it and I have over a million miles on all of my cars and I have owned most of them the majority of there miles. Good Luck

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I like to Drive
77 Celica GT 295000 sold
80 Volvo DL 168000 sold
84 Volvo GLT 342000 Real fast sold
86 Crown Vic. 258000 cheap to keep
84 Ford Van 6.9 360000 sold Great
88 Ford Dulley 7.3 311000 still have
90 Ford Van 7.3 235000 sold great
92 Ford Van 7.3 223000 Excellent still have
82 300TD 1st Benz Great Car 205000Sold
85 300SD 245000 What a ride
84 300SD project car with son, Rod knock
85380SE What a RIDE
90 420SEL Nice Ebay Addition Great buy