0-40 in 2013 GMC Terrain 6 cylinder? smaller 4 cylinder?

[Wolfkc]

I browsed through some reading on this site a few years ago and got the impression that generally you can't, at least without special ordering, you can't go to low on the first number and 40 is better than 30 for the high number.
So in general even if my engine recommends something else, for a 2013 GMC Terrain 6 cylinder isn't 0-40 always better than all the typical oil change options that oil places offer or suggest like 5-20, 5-30. I always get synthetic and a "good" brand typically Mobile, Castrol or valvoline. Let's keep this discussion to the oil viscosity.
So, should I keep ignoring the strange looks and questions when i ask for this oil? I don't want to special order anything, but even walmart carries Mobil 0-40.
Does my idea that "0-40 is better than 5-30 or 5-20 apply to smaller engines like my GF's 2008 Honda CRV 4 cylinder?
Also I don't care at all about loosing a tiny bit of gas mileage to extend my engine life even a small amount.

Thanks in advance, Kerry

 

[JLTD]

Lots of guys using 0w-40 on here, for everything, with good results.

That said, in TX you will probably never actually need a 0w oil, probably 10w might suit depending on whether you're north or south.

 

[oil_film_movies]

Usually its fine to go thicker one grade over what the Owner's Manual recommends..... Your 2013 engine calls for 5w30, so going to the slightly thicker 0w40 won't be a problem. For the Honda you mention, it originally called for an xw20 oil when new. Since its old now, a 0w40 would work for it too, although I'd probably put in a 5w30 in the Honda.

One reason to use a 0w40 (in a 5w30 application engine) is that 0w40 oils are built to pass tougher specs than dexos1. Mobil1 0w40 passes Mercedes 229.5 and Porsche A40, tough specs, so you know thats great oil. Walmart's price on Mobil1 0w40 is awesome for what you get.

 

[CT8]

May I ask, what would engine size have to do with oil viscosity?

 

[addyguy]

0W-40 is generally a good thicker oil to go to if one wants.

That era of GM V-6 and 4-cylinder engines also often had timing chain wear problems, so going to a 40-weight in TX def. would not hurt.

 

[oil_film_movies]

Originally Posted by CT8
May I ask, what would engine size have to do with oil viscosity?

The Reynolds number would be higher on a larger engine. Unless.... the smaller engine ran at higher RPMs (which they usually do) to compensate, in which case the Reynolds number wouldn't change in a big vs. small engine.

 

[JLTD]

Originally Posted by oil_film_movies
Originally Posted by CT8
May I ask, what would engine size have to do with oil viscosity?

The Reynolds number would be higher on a larger engine. Unless.... the smaller engine ran at higher RPMs (which they usually do) to compensate, in which case the Reynolds number wouldn't change in a big vs. small engine.


My brain hurts. English please.

https://www.youtube.com/watch?v=VCzsX-LqJ-4

 

[oil_film_movies]

About Reynolds number, in an engine, the value of the ratio of inertial to viscous forces merely determines the shape of the velocity profile between the shearing surfaces. The much higher bearing forces dominate enough to say Reynolds number isn't really a big issue. Besides, smaller engines generally run faster anyway, meaning Reynolds numbers are ~about the same comparing say a Hemi to an S2000 engine.

 

[oil_film_movies]

Sorry about geekiing out on what the differences might be per viscosity in a big vs. small engine.
It reminded me of similitude fluid mechanics, and Reynolds number is important when trying to calculate drag and separation issues.
Worth a look anyway ! I'll flash the 'Men In Black' light now so you can carry on unimpeded with your lives. ..... Smoke'em if you got'em.

 

[JLTD]

Originally Posted by oil_film_movies
Sorry about geekiing out on what the differences might be per viscosity in a big vs. small engine.
It reminded me of similitude fluid mechanics, and Reynolds number is important when trying to calculate drag and separation issues.
Worth a look anyway ! I'll flash the 'Men In Black' light now so you can carry on unimpeded with your lives. ..... Smoke'em if you got'em.


Thanks.....for all the posts.


https://www.youtube.com/watch?v=gPIhKLmO7WU



Now where was I?

 

[mightymousetech]

Originally Posted by JLTD
Lots of guys using 0w-40 on here, for everything, with good results


Agreed.

See sig.