Jim Grant's Tech Tips

Dodge Truck, Synthetic Oil Use
Q: We just picked up our Dodge B2500 4X4 5.9 Liter Diesel a few days ago and I am trying to decide whether to switch to synthetic oil or not. I am a believer that it is vastly superior to conventional oil. A diesel is a dirtier engine than a gasoline one. How do synthetic oils perform for diesels? What weight would I use for the diesel? We plan on traveling upon retirement, pulling a 5th wheel or a trailer. We hope to keep this truck forever! I would appreciate your answer....Doug & Suzie

A: This may surprise you but synthetic oil is listed as an approved lubricant for the engine of your vehicle. Check your Owner’s Manual, I believe the oil has to have a minimum API Service Grade rating of CF-4 or CG-4. You can find the API Grade Rating listed on the oil container. I agree that synthetic is a better grade of lubricant to use in your engine. But! Don’t think for one moment that you can run the oil any longer or beyond the manufacturer’s recommended service intervals. Many synthetic oil producers will state that their oil can be run for extended mileage, over and above vehicle manufacturer’s service recommendation. I have yet to see any of these companies put in writing that, if a problem arises with the engine, they will step up and fully warranty the vehicle’s engine. Synthetic is great-go ahead and use it, but always follow the manufacturer’s recommended service intervals while the vehicle is under warranty. After the warranty is up, you do as you please.