5W-40 All year round?

[Volvohead]

Originally Posted By: Swift101
. . . I don't want to pay more for a 40 grade oil if I can get a 5 quart Jug of 5W-30 at Walmart for $25. . .


If all this is being motivated by COST, then why don't you just do what the last poster suggested and use M1 0w-40 ($26/jug at WM), which is a more robust oil choice than any 5w-30 you are going to find in their oil aisle, and at least somewhat approaches the 5w-40 that the manufacturer recommends.

 

[Jasper8146]

Even though they are both 5W oils, there is a huge difference in cold viscosity between 5W-30 and 5W-40 no matter what the brand and whether it be conventional or synthetic. If you go to the technical properties page of any oil manufacturer website, you can see that is true. Likewise, there would be a substantial difference in operating viscosity as well. Whether you need thicker or thinner depends on your engine and manufacturer recommendation. But, for any extremely cold climate, 5w-40 is going to be really thick at start-up. That's why it's impossible for me to understand why Hyundai recommends 5W-40 in their 2.0T turbo engine for CANADIAN users. Seems like that would be a better recommendation for Florida and Southern California and Arizona users.

 

[Garak]

Originally Posted By: Jasper8146
That's why it's impossible for me to understand why Hyundai recommends 5W-40 in their 2.0T turbo engine for CANADIAN users.

Maybe Hyundai has been reading my incessantly complaining posts about how Delvac 1 5w-40 is similarly priced to conventional oils in Canada.

See, we're backwards up here.

 

[HTSS_TR]

Originally Posted By: Jasper8146
Even though they are both 5W oils, there is a huge difference in cold viscosity between 5W-30 and 5W-40 no matter what the brand and whether it be conventional or synthetic. If you go to the technical properties page of any oil manufacturer website, you can see that is true. Likewise, there would be a substantial difference in operating viscosity as well. Whether you need thicker or thinner depends on your engine and manufacturer recommendation. But, for any extremely cold climate, 5w-40 is going to be really thick at start-up. That's why it's impossible for me to understand why Hyundai recommends 5W-40 in their 2.0T turbo engine for CANADIAN users. Seems like that would be a better recommendation for Florida and Southern California and Arizona users.

Why Honda recommends 5W40 in colder climate in place of 10W30 for S2000 ?

 

[Garak]

Such a recommendation by Honda does make sense, at least if one is looking at cold cranking values. Look at the "standard" diesel recommendation - 15w-40 summer, 10w-30 winter, 5w-40 (or even 0w-40 or 0w-30) in Arctic conditions.

 

[Shannow]

Originally Posted By: Garak
Look at the "standard" diesel recommendation - 15w-40 summer, 10w-30 winter, 5w-40 (or even 0w-40 or 0w-30) in Arctic conditions.


Interesting point...see
http://www.aftonchemical.com/ProductDataSheets/Lubricant Components/HiTEC-5710_PDS.pdf

Down the bottom table, with the 3 and 4cst oil...10% VII makes a nominally one grade heavier oil...with a lower pour point.

Particularly before the HTHS for 0W, 5W, and 10W were raised to 3.5 from the previous 2.9, specifying a 5W-40 would give you 30grade HTHS, and possibly better low temperature behaviour from the greater addition of VII.

 

[Kuato]

Wow, this has gone round and round....

I go back to the manual posted by OP...and to quote:

Originally Posted By: Swift101

"Lower viscosity engine oils can provide better fuel economy and cold weather performance, however, higher viscosity engine oils are required for satisfactory lubrication in hot weather."

Italics are mine... but OPs use of a 40 weight oil in summer in NYC where temps hit the 90s for much of the summer...is strongly encouraged by the manufacturer.

Yes a 5w30 will probably do just fine. But OP's original question was about using 5w40 year round. And although most 5w30 will be a bit thinner at startup in the cold than a 5w40, this could be gotten around by using a 0w40.


Add to this discussion the fact that European and Australian specifications require a higher weight oil for most manufacturers, and OP's plan sounds better and better.

 

[Garak]

Originally Posted By: Shannow
Particularly before the HTHS for 0W, 5W, and 10W were raised to 3.5 from the previous 2.9, specifying a 5W-40 would give you 30grade HTHS, and possibly better low temperature behaviour from the greater addition of VII.

That's certainly possible, and worth noting when looking at oil recommendations from outside North America and trying to understand them, particularly from a historical perspective in light of the piecemeal editing of these owners' manuals.

 

[A_Harman]

Originally Posted By: Shannow

Interesting point...see
http://www.aftonchemical.com/ProductDataSheets/Lubricant Components/HiTEC-5710_PDS.pdf

Down the bottom table, with the 3 and 4cst oil...10% VII makes a nominally one grade heavier oil...with a lower pour point.



That's an interesting chart. It gives really good insight into the effect of a VII on base oils. Afton's Hitec 5710 is a liquid polymethacrylate. Adding 10% of it to a base oil will have the following effects:
Increase KV100 from 4.1 to 13.69 cSt.
Increase VI from 95 to 234.
Lower the Pour Point from -18 C to -45 C.