Can I top off a diesel with gasoline oil?

[Oil fan 47]

Would you feel comfortable topping off a diesel engine with gasoline oil?

I've got a 6.7L turbodiesel in my 2021 F-250. It takes 13 quarts of diesel oil, but I've only got 12 quarts of T5 10W-30 on hand. Is there any reason I shouldn't be able to use gasoline oil for that final quart?

According to my calculations it would make the composition of the oil about 93% diesel oil and 7% gasoline oil. At what concentration of gasoline oil would you begin to be concerned?

 

[meadows]

Drive it to Walmart to buy another quart.

 

[dogememe]

Buy another gallon of the right oil, you’ll need it next time anyway…

 

[walterjay]

I have done it in a pinch when my box truck was about 3 qts low from neglect. I put it on the road like that for a few days until I could change it out with the proper oil. In your case I recommend you get the right stuff and forego the gasoline oil.

 

[fdcg27]

I'd do it.
One quart in thirteen ain't gonna make any measurable difference.

 

[fantastic]

If you have one quart out of 12 it will be fine but I wouldn't make a habbit out of it. If you haven't bought the Gasoline rated oil yet just buy the quart of diesel oil you need.

 

[cptbarkey]

What is the final quart of gasoline oil are you considering?

 

[FowVay]

Shell Rotella T-5 10W-30 oil with the CK-4 rating is a very impressive product. If this is your oil change then I would make the effort to fill the sump with the proper amount of T-5.

If you're three quarters of the way through an oil drain interval and you're in the middle of nowhere on a Sunday night with the only option for a top-off quart is some truck stop then you do what you have to do. But if you're doing a service-fill then do it correctly.

 

[atikovi]

Why not just drive it on the 12 quarts diesel oil until you can get an additional quart? Being 1 quart low out of 13 won't be a problem. Better than contaminating 12 quarts of fresh oil.

 

[Oil fan 47]

What is the final quart of gasoline oil are you considering?

I've got some Warren made Kirkland 5W-30.

 

[kschachn]

How far in the boondocks are you exactly?

 

[mattd]

I’d run it a quart low until you can make it back to buy the correct oil. It won’t hurt it.

 

[Shel_B]

I'd do it.
One quart in thirteen ain't gonna make any measurable difference.

It does make a measurable difference as noted above. Perhaps you meant that it's not a meaningful difference?

 

[Oil fan 47]

How far in the boondocks are you exactly?

Not far. The question is mostly academic, but it would be nice to not have to make a trip to the store for a single quart.

 

[Shel_B]

I've got some Warren made Kirkland 5W-30.

Don't do it. Top off with the appropriate Diesel oil.

 

[cptbarkey]

I've got some Warren made Kirkland 5W-30.

its slightly not right. Also, you came into a forum full of sharks that will ponder on this endlessly.

If you can, go get 1 more quart of the good stuff. Otherwise the entire time you drive that nice truck, you will know you put 1 quart of the slightly not right stuff inside.

Welcome to BITOG. Your engine might explode, it might be fine. Good luck.

https://www.fordservicecontent.com/Ford_Content/vdirsnet/OwnerManual/Home/Content?variantid=7002&languageCode=en&countryCode=USA&Uid=G2019832&ProcUid=G2019838&userMarket=usa&div=f&vFilteringEnabled=False&buildtype=web

 

[Shel_B]

Not far. The question is mostly academic, but it would be nice to not have to make a trip to the store for a single quart.

Perhaps you can buy more than a quart. If you can afford the storage space and the coin, buy the needed quart + enough oil for your next change. Pick up a filter or two, and be ahead of the game.

 

[Passport1]

If you were making a vodka martini and discovered you lacked enough vermouth would you just add enough sherry to make up the difference?

 

[kschachn]

The bottom line is that it would be fine. But if this is only academic and there isn't really a need to do so then don't. It likely will not have the proper license or specification listed in the owner's manual.

 

[tnt_motorsports]

FWIW I’d run it 1 quart low before I added PCMO to my high dollar diesel engine. By the OPs math you’d be running the engine 7% low.

Just my $0.02