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Is Synthetic Oil Bad for Diesel Engines?
Ask Your Stickiest Question. . . Or ask us something you’ve always wanted to know about using our products. We’ll sort through all the submissions and present the best questions to our automotive experts. We'll share the questions and their answers here.
Is Synthetic Oil Bad for Diesel Engines?
I own a 2007 Ford 6.0 liter diesel F250, and was told at the dealership that Mobil 1 would void my warranty. Also, people I talk to swear that synthetic oil is bad for diesel engines.  Why is this statement being made? I swear by Mobil 1 and won't use anything but.
-- Pete Soderling, Pueblo West, CO
We have an outstanding Mobil 1 diesel oil for diesel engines and it is called Mobil 1 Turbo Diesel Truck.  Since this product is a 5W-40 engine oil it would be perfect for your vehicle especially since it can get pretty cold in Pueblo West in the winter and pretty hot in the summers. The 5W-40 viscosity will protect on both ends of the temperature spectrum. The product was recently reformulated and upgraded to API CJ-4, and it continues to meet older categories such as API CI-4, CH-4, etc. With the exception of Mobil 1 Turbo Diesel Truck, you should not use other Mobil 1 products in your diesel engine.
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