The best of the Mobil oils for diesels is the Delvac 1 synthetic 5w-40 from all the testing done over at the VW TDI forum. Somewhat higher soot capabilities then Delvac1, greater temp range (big cold range difference), much higher load bearing range (common to all synthetics vs dinooils) and can be bought under the name of Mobil 1 Truck & SUV oil at Wal-Mart under $5 a qt.

In our high soot creating ALH TDI VW's (turbo diesels)this oil can easly go 15,000 to 20,000 miles between changes, by doing one filter change and top off at the half way point. These cars have problems with high soot content being pumped into intake mixing with oil from CCV then clogging engine intakes.

I have done a switch from dino to Delvac 1 (not Delvac 1300) and have done 2 flushes with said oil and when I get to about 4500 miles on the oil I will send in a sample for testing and see how the old girl stands.

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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.