10w30 SP in a Cummins
- Thread starter cneal
- Start date
Short-term, nothing. But you'd be foolish to keep it that way IMO. That's not a diesel rated oil and towing really isn't the issue.
I can't think of a valid reason why it should remain in there any longer.
I can't think of a valid reason why it should remain in there any longer.
Tell him that without the extra detergents and dispersants in the diesel oil, he will eventually see a nice layer of soot built up on the inside of his engine. The ring pack will also become sticky and his engine will start using oil and the power will decrease.
Never ever run a gas engine oil that does not have the appropriate ratings in a diesel.
Never ever run a gas engine oil that does not have the appropriate ratings in a diesel.
Were there signs that he shouldn't marry your daughter before this?
Delvac 1300 is 10w-30 and SP rated so it was probably that. If he used the 5 quart silver jug of 10w-30 then I'd drain it out soon but it's not gonna blow though pcmo 10w-30 is FA-4 in terms of hths and i never liked 10w-30 being recommended for diesels because people might put 10w-30 FA-4 by accident and have an oil that's too thin.
Also ram is silly for saying you can use 10w-30 but not 15w-40 and instead have to use 5w-40. But 10w-30 and 15w-40 can be made in conventional and syn blends and from the pds's i've seen when noack is avaiable the 15w-40 always has a lower noack and higher flash point even on cheap conventional and syn blends. The problems come from their new valvetrain not the oil. Higher noack and more volatile 10w-30 would cause more problems than 15w-40 if the oil was the issue.
Also ram is silly for saying you can use 10w-30 but not 15w-40 and instead have to use 5w-40. But 10w-30 and 15w-40 can be made in conventional and syn blends and from the pds's i've seen when noack is avaiable the 15w-40 always has a lower noack and higher flash point even on cheap conventional and syn blends. The problems come from their new valvetrain not the oil. Higher noack and more volatile 10w-30 would cause more problems than 15w-40 if the oil was the issue.
CleanSump
Site Donor 2026
CK-4 according to the owners manual. Mobil Delvac if he prefers Mobil.Well….which Mobil 1 oil exactly? Maybe check the jugs to verify if it’s appropriately Diesel rated, as lotsa diesel oils also have a gas rating
From wear to early oil change needed. Dump it & get CK-4 10w-30. That is if you're talking about a non "C" rated oil, right?