In a hurry, bought 15w40 when I should have bought 5w40. Changing it out today but the question is, will leaving the oil that's in the filter be ok, or just suck it up and drain it too and buy a new filter?

Thanks!

 

It won't hurt a thing. You might want to put in a quart less than the full amount initially, check your oil, and maybe add from there if you need to.

 

15W40 is fine for your 6.7 and there are more approved 15W40 oils on Ford's approved list than any other weight.

https://www.fcsdchemicalsandlubrican...SSM2C171F1.pdf

If it were me, I'd leave it and go to 5W40 on your next change if so desired.

 

OMG don't waste that oil!
Leave it in there and get the use out of it for the duration of the IOLM.
15w-40 is not a "wrong" viscosity. It's an approved vis on Ford's list.
I understand it's not the one you may have wanted, but for goodness sake don't fall victim to the internet hype about syns and vis.
Use it to it's full potential; run out the IOLM.

 

15W-40 Motorcraft is all I use. Unless you live in a really cold climate a little lighter may be better.

 

Yeah, I live in Colorado and it was 15 degrees out this morning and it's going to get colder.

 

15 is a little heavy for those temps for sure. And it is going to get colder.

 

Lie was posted above, don't sweat it. Run it. I live in Colorado also and would run it in a heartbeat.

Sam

 

Drain it and replace it you will sleep better and not think about it again. Always tightwads who will drive 10 miles to save a dime on something. Bottom line if it bothers you replace it-----I would if it bothered me...

 

 

I don't think it's fair to call someone a tight wad because they don't worry about the same things as you. (Me, I spend money like a drunken sailor...) I think it's more of a, "what concerns the individual" situation. Personally, being in CO in winter with 15W40 oil would't worry me. However, there are things that would worry me and not someone else.

 

Nailed it--there ya go.....

OK maybe tightwad wad is strong for some BUT I personally know people who are like that and who have done that they had oil for another vehicle they traded and refused to not use it. Was a corvette C7 but still kind of the same thing.

 

I think most sae 15w oils are rated to -4

 

15w-40w oil is fine in diesels for most of Colorado. Most people think we all live up in the mountains. The truth is the majority of us live either on the western slope of the Rockies or out on the plains (e.g. Denver, Ft Collins, Greeley, etc). While it can get cold here at times, it's not like living up in the Dakotas or Minnesota.