Is there any significant difference between synthetic oil for diesel engines vs. gas?

Sorry, I meant for the 3500 with the 3.0 turbo diesel engine...

Also, the dealership that sold us the vehicle delivered it with 15-40 oil and Mercedes Benz dealership says that the proper oil viscosity is 5-30...... normally I would trust the Mercedes Benz dealership.. your opinion.??

Oil needs to meet the Mercedes spec. MB 229.52. 0w30 or 5w30 would work if it meets the spec. See the link....http://www.sprintervandiaries.com/2016/06/17/sprinter-oil- change/

If link does not work remove the "space" between - and change.

Good morning Bob-. Thank​ you for your reply... My issue is that the dealership who sold me this vehicle at 26,000 miles and in spectacular condition told me that they changed the oil exactly like the previous oil changes with 15-40 oil ... I found the previous oil change sticker on the inside of the windshield at 21,000 miles... also stated 15-40... Maybe the dealership didn't know?? They​ took this vehicle in trade from the original owners.. who wanted to get a larger vehicle than this one.. The vehicle drives and responds great.. When I took the vehicle to Mercedes Benz for warranty work on the recalled Takata passenger airbag, they told me that there were no records in their system for oil changes.... that's typical if individual owner's have work done outside the dealership network. That doesn't concern me.... BUT, they advised me to pick up a couple of quarts of oil and keep handy if I needed it...not a bad idea,. Now, I'm faced with the dilemma of having 15-40 in the engine and having 5-30 on hand for oil if I found I needed to add any oil....! I live in Los Angeles CA and it does get pretty hot here in the summer, so, maybe 15-40 is OKAY, but, I try to run the manufacturers recommended viscosity ?? I could always just have the oil changed back to 5-30 now???? I've only had this vehicle for a month, and have put 500 miles on it, what would you do? ----Mark

15w40 in a warm climate probably will cause no issues, but I have always supported running the proper oil grade as recommended by the manufacturer. I would wait until it's time for the next oil change and switch to 0w30 or 5w30 or 0w40 that meets the Mercedes spec. You will need a euro. spec oil. Go to the Mobil1 site and enter the vehicle info., the 0w40 might be the easiest to find. Since it has a turbo I would run a synthetic oil.

Bob, found this online from a guy who specializes in Mercedes Benz vehicles.... Link and operative language following... Bottom line is that he's saying that 15-40 is actually a good idea... http://www.stephensservice.com/did-you-know/

OWNING A “BLUETEC” DIESEL. ,- from the above-mentioned The Bluetec diesel has a exhaust driven turbocharger. That means the hot exhaust going out the tail pipe is also used to turn the turbocharger. It’s a very efficient way to produce extra power. But, it has a dark side. The exhaust temperature routinely runs at over 1200F. When you shut the engine off, that heat literately destroys the engine oil. Even the very best synthetic diesel motor oil will breakdown & revert back to tar, at 600F. If you read the Mercedes- Benz owners forums about the OM642 diesel engine, you will see hundreds of owners with long list of complaints. It does not need to be like this. The OM642 diesel is a good engine. If you change the oil every 5000 miles and use Redline 15W/40 Diesel oil, you will have far fewer problems. Change the engine Air Filters every 20,000 miles and it will greatly reduce Blow-by. Change the Oil Separator at the first sign of oil leaking from the Turbo. (We’ve seen owners that have wasted thousands of dollars trying to fix oil leaks that are caused by the Oil Separator.) Owners think they must go to the dealer for service when their car is new. Dealers lead them to believe it is a warranty requirement. This is not true. The sooner a new car starts using better oil and more frequent oil changes, the fewer problems it will have. We’ve seen so many so called “experts” tell owners to follow the manufacture recommendations. This is a sure fire way to ruin the engine and end up outrageous repair bills. We can prove what we say with Mercedes-Benz own service bulletins.

I get my vehicles​ serviced religiously..... it's something I have done for years and while it does cost more, my breakdowns are very infrequent...and I usually sell my vehicles for a lot more when I sell them....in other words, it pays to keep them going...

I agree that changing the oil, filters and other critical components is the cornerstone of keeping your car on the road....

Good news, found out today that the dealership who sold me the Sprinter did in fact use 5-30 Mercedes Benz oil.....